[HN Gopher] So you want to study mathematics
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       So you want to study mathematics
        
       Author : musgravepeter
       Score  : 255 points
       Date   : 2022-03-07 18:05 UTC (4 hours ago)
        
 (HTM) web link (www.susanrigetti.com)
 (TXT) w3m dump (www.susanrigetti.com)
        
       | tunesmith wrote:
       | How do you like to solve math problems in this day and age?
       | 
       | I'm partial to Jupyter notebooks lately - I run it locally from a
       | docker container, and have a folder of notebooks. Mostly markdown
       | cells, alternating between my narrative thinking and LaTeX math
       | output.
        
         | bnbond wrote:
         | I find paper and pencil works pretty well.
        
       | paulpauper wrote:
       | You don't need so many books. many of the old texts will cover
       | many important college-level concepts in a single source.
       | 
       | https://www.gwern.net/docs/statistics/1957-feller-anintroduc...
       | 
       | this is linear algebra + combinatorics + probability + stats
       | 
       | If you understand the material in this one book it's reasonable
       | to say that you are pretty good at math
        
         | ChrisLomont wrote:
         | At a first glance that book completely fails for an undergrad
         | lin alg course, and looks weak in other areas too.
         | 
         | Examples: the words nullity and kernel don't appear, rank of a
         | matrix is not in it, and, well, every topic I can think of for
         | undergrad linear algebra is simply not in the book.
         | 
         | It's equally bad for stats: no mention of many common
         | distributions a student would learn for example.
        
           | wizzwizz4 wrote:
           | Is that such a bad thing? I'm half-convinced that the "rank
           | of a matrix" is just an artefact of a particular algorithm
           | for inverting matrices. And distributions aren't everything;
           | I can look up any distribution I want on Wikipedia, just as
           | soon as I need it, but a proper foundation in what statistics
           | _means_ is much harder to come by. (I have enough of a
           | foundation to know when it 's being taught very wrong, but
           | not enough to actually be very useful in day-to-day life.)
        
       | philomathdan wrote:
       | The curriculum guides Susan Rigetti provides are an amazing
       | resource for self-study. And the fact that she worked through all
       | of this is truly inspiring.
       | 
       | Not to be greedy, but do any of you know of other thorough
       | curriculum guides like this? I know about
       | https://teachyourselfcs.com already -- another amazing guide. Are
       | there others? I would love to find one for statistics especially,
       | but really any subject would be interesting.
        
         | Jun8 wrote:
         | Susskind's Theoretical Minimum is fantastic for physics self
         | study: https://theoreticalminimum.com/
        
           | philomathdan wrote:
           | Another good one. Thanks!
        
       | da39a3ee wrote:
       | I am fairly confident that Susan Rigetti is a future president of
       | the USA. In addition to becoming somewhat well-known as a
       | household name early on in her adult life, she has achieved so
       | many difficult and impressive things (publishing multiple books,
       | studying physics and philosophy at graduate level, working for a
       | top-tier tech company, taking down the CEO of a top-tier tech
       | company and damaging the company's reputation, being asked to
       | work for the New York Times, publishing curricula in graduate
       | Physics, graduate Philosophy, and undergraduate mathematics).
       | Furthermore, she seems to have a gift for or knack with the
       | public eye.
        
         | rscho wrote:
         | POTUS is a very low bar...
        
       | potbelly83 wrote:
       | As a math PhD I have to say the only way you're going to learn
       | mathematics is if you actually have a pressing need to do so.
       | i.e. You have a project at work that needs some math, you have a
       | hobby that needs some math. In this case you just learn what you
       | need. Just learning math for its own sake outside of a University
       | STEM track is just too hard (I wouldn't be able to do it and I've
       | tried).
        
         | JimTheMan wrote:
         | I think the question needs to be asked, "What am I hoping to
         | get from this?"
         | 
         | If its tools to help you solve some problem, great. If its
         | because you find it fun, great.
         | 
         | But if its because you feel you want to 'better yourself' or
         | perhaps feel like it would somehow prove your intellectual
         | worth, you probably won't get a lot out of it.
        
         | treeman79 wrote:
         | Was programming a 3-axis machine in early college back in 90s.
         | After a few months I was mostly re-inventing trigonometry. The
         | I actually took trig later on. That would have been super handy
         | at time.
        
         | kurthr wrote:
         | I hesitate to contradict someone who has gone through the whole
         | Math PhD process, but I have to say that the best
         | mathematicians that I know treat the problems they're working
         | on as games, or riddles to be solved... and they've taught
         | their kids (and others) this same method of thinking about
         | these problems. There's a huge mental tool set, and often a lot
         | of grinding to get to a solution, but it's just a game (and
         | there are often more elegant solutions)!
         | 
         | I enjoy provoking interest in complex numbers and exponentials
         | among precocious teens, but I've never been more humbled than
         | having a Galois theory joyously explained to me by an 11 year
         | old. (p.s. I'm an engineer so I follow your technique).
        
           | 300bps wrote:
           | To me the problem isn't learning it, it's retaining it.
           | 
           | I learned all kinds of quantitative analysis and statistics
           | in the CFA program ten+ years ago.
           | 
           | I had daily sheets that I would solve equations and answer
           | all kinds of questions. I knew them forwards and backwards. I
           | just looked at one now on fixed income - not sure if could
           | answer any of the questions today to save my life.
           | 
           | And I work in finance daily!!
        
         | [deleted]
        
         | Grambo wrote:
         | I experienced something like this recently. I struggled to
         | grasp linear algebra when I took it in undergrad and as a
         | result was always intimidated by the subject. Now, years later,
         | I'm taking a course in graphics and naturally needing to
         | relearn linear algebra and suddenly everything just clicks.
        
         | zinclozenge wrote:
         | This is true. When I started my first job, I tried casually
         | learning more from where I stopped after I finished school. My
         | motivation slowly waned as I realized I vastly preferred
         | playing video games than watching lectures and trying to do
         | some problem sets.
        
         | exdsq wrote:
         | Correct me if I'm wrong, but I assume you're looking at this
         | through the wrong lens. As a PhD you've learnt something hard
         | at a considerable depth but this isn't what I, or most people,
         | hope to achieve by learning maths themselves. It's normally to
         | a far lower depth that's far more achievable like Calculus I or
         | some aspects of number theory or knowing what all the funky
         | symbols such as Summation mean.
        
       | parsd wrote:
       | If you're interested in both mathematics and physics, does it
       | make sense to learn both concurrently? If yes, what areas
       | complement each other? Or is there no overlap to warrant
       | concurrent study of the essentials? By essentials I mean what a
       | college student must know, or really anyone who pursues self-
       | education without a background in these areas. Beautiful website,
       | by the way!
        
         | susanrigetti wrote:
         | Check out my physics guide:
         | https://www.susanrigetti.com/physics. It has both the physics
         | core curriculum AND the math essentials you need to know in
         | order to understand the physics essentials. (And thank you!)
        
       | C-x_C-f wrote:
       | The website mentions some good courses, personally I love Richard
       | Borcherds' YouTube channel[1] for both undergraduate and graduate
       | courses. No frills, exceptionally clear, (mostly) bite-sized
       | lectures that cover a good range of material (especially in
       | geometry).
       | 
       | Something that might interest HN's demographic is Kevin Buzzard's
       | _Xena Project_ [2], centered around proof systems (in Lean). The
       | natural numbers game [3] is particularly fun IMHO. I don't know
       | if it counts as learning materials per se but it's certainly
       | instructive.
       | 
       | [1] https://www.youtube.com/channel/UCIyDqfi_cbkp-RU20aBF-
       | MQ/pla...
       | 
       | [2] https://xenaproject.wordpress.com/
       | 
       | [3]
       | https://www.ma.imperial.ac.uk/~buzzard/xena/natural_number_g...
        
       | brimble wrote:
       | Are there any "math for people who just want to use it" tracks in
       | math pedagogy? I don't care a bit about proving any of it's true,
       | or even reading others proofs of same. "Recognize which tool to
       | apply, then apply tool", all focused on real-world use (so, yes,
       | it wouldn't be "real" mathematics). That's the math education I'd
       | like--try as I might, I just can't make myself care even a little
       | about math for math's sake.
       | 
       | I've got _Mathematics for the Nonmathematician_ by Kline and that
       | 's kinda heading the right way, but what about whole courses of
       | study? More books? It's more of an introduction than a thorough
       | resource or course, and feels like it needs another four or five
       | volumes and a _lot_ more exercises to be really useful.
       | 
       | I want a mathematics education designed for all those kids
       | (likely a large majority?) who spent math from about junior high
       | on wondering, aloud or to themselves, why the hell they were
       | spending _so much_ time learning all this. One that puts that
       | question front and center and doesn 't teach a single thing
       | without answering it really well, first.
        
         | dwohnitmok wrote:
         | > I want a mathematics education designed for all those kids
         | (likely a large majority?) who spent math from about junior
         | high on wondering, aloud or to themselves, why the hell they
         | were spending so much time learning all this. One that puts
         | that question front and center and doesn't teach a single thing
         | without answering it really well, first.
         | 
         | The problem is that the answer will depend heavily from person
         | to person and from field to field and often the most sensible
         | answers require a mathematical maturity that creates a chicken-
         | and-egg kind of difficulty.
         | 
         | Do you care about engineering? Well you'll need some calculus
         | for that. Do you care about prediction modeling? Well there's
         | some stats you'll need for that. Do you care about finding
         | patterns in the world? Well there's abstract algebra for that.
         | Do you care about reasoning itself? Have fun with mathematical
         | logic. But because humans have different motivations, there's
         | no one-size-fit-all motivation-based approach.
         | 
         | This is especially painful for mathematics because I think most
         | people who have learned some amount of pure mathematics will
         | relate heavily to what helpfulclippy says in a sibling comment:
         | "However, one thing that has been VERY applicable is
         | proofwriting. Although math proofs are far more rigorous than
         | most real world stuff, the discipline I learned in writing
         | proofs has carried over into pretty much everything from
         | programming (will this algorithm work every time?) to executive
         | decisions (why, specifically, should we believe X?)."
         | 
         | The skills of rigorous and abstract thinking that pure
         | mathematics provides is both nearly-universally helpful, but
         | also simultaneously as a result very difficult to motivate.
         | "This will help you think better across everything you do" is
         | lofty-sounding, but generally not a convincing sell unless
         | someone is already curious. But it's true that being able to
         | wrap one's mind around pure abstraction (after rattling off a
         | rigorous definition for an abstract question: Question: "But
         | what is X _really_? " Answer: "X is just that. No more, no
         | less.") has ramifications for all that one does.
         | 
         | And the most painful part of all of this is if you try to start
         | by teaching the wonders of pure mathematics instead of all the
         | messy, boring rote stuff, students' eyes are liable to glaze
         | over even more because of the aforementioned chicken-and-egg
         | issue with mathematical maturity.
         | 
         | In this way it's similar to trying to motivate someone to read
         | and write. The key that unlocks that interest for everyone is
         | going to be different and it's very hard to explain the near-
         | universal benefits that reading and writing bring to one's way
         | of thinking (but I can always just have a computer transcribe
         | it or read it aloud to me!) without some inherent curiosity in
         | them.
        
         | joatmon-snoo wrote:
         | My strong opinion as someone who majored in math is that, at
         | least within the US, the standard calculus requirement should
         | be replaced with statistics. So much more useful and so much
         | more important as an adult.
         | 
         | The analytical type of thinking that proof-writing is certainly
         | useful, but you can make much the same argument of many other
         | curricula, and besides, it's not like most intro calc courses
         | even do any proofs. The vast majority of them, I would assert,
         | are simply pre-med weed-out courses.
         | 
         | I still remember freshman year, showing up to the standard
         | intro calc course, and dropping it as quickly as I could in
         | favor of my uni's equivalent of Math 55 (i.e. the hardest u/g
         | intro math course) because of how asinine I found the
         | content...
        
           | jldugger wrote:
           | > My strong opinion as someone who majored in math is that,
           | at least within the US, the standard calculus requirement
           | should be replaced with statistics. So much more useful and
           | so much more important as an adult.
           | 
           | Strong agree, but engineers probably need both. I'm currently
           | watching a course on causal inference, and the tools are very
           | much calculating gradients. And even if you just use someone
           | else's MCMC, even in the models a differential equation or
           | integral can randomly appear usefully.
           | 
           | In retrospect I should have taken a stats class in high
           | school when I had that 1 hour gap for 1 semester, just to
           | build a better intuition around the basic concepts.
        
           | jpz wrote:
           | You can't understand much about statistical inference without
           | calculus.
           | 
           | It's all integrals over pdf's. A lot of integration by parts
           | and other things in the core curriculum.
        
           | dwohnitmok wrote:
           | FWIW (and I know you're not making this claim) I don't
           | believe Math 55 is a good example of how mathematics should
           | be taught at large, nor do I think calling it an intro class
           | accurately conveys what it is. It's effectively the
           | compression of an entire undergraduate degree into a single
           | freshman course. I say "effectively" because the material
           | covered depends heavily on who's teaching it, but certainly
           | anyone coming out of Math 55 can pick up any undergraduate
           | math content trivially. For example, undergraduates who have
           | taken it are generally explicitly prohibited in course
           | descriptions from taking further undergraduate mathematics
           | classes (because it would be free credit for retreading the
           | same ground) and can only take graduate courses from then on
           | out.
           | 
           | It's strongly self-selecting and as a result can afford to
           | cover a truly insane amount of ground. The overwhelming
           | majority of people who take it drop out (the usual dropout
           | rate from people who take it in the first week is probably >
           | 90%), but the people who stay almost all get As. And you will
           | need to be almost entirely self-motivated because a lot
           | (maybe most) of your waking hours will be thinking about
           | math.
           | 
           | There's a very small minority of students for whom this is an
           | optimal way of learning. For most students this is the
           | quickest way to make them run screaming away from mathematics
           | even faster than they already do.
        
             | C-x_C-f wrote:
             | > For example, undergraduates who have taken it are
             | generally explicitly prohibited in course descriptions from
             | taking further undergraduate mathematics classes (because
             | it would be free credit for retreading the same ground) and
             | can only take graduate courses from then on out.
             | 
             | Not at all, you are only prohibited from taking "freshman
             | courses"[1]--that's what 55 is supposed to cover
             | (definitely _not_ all of the undergrad math curriculum),
             | though some professors go beyond that. Many students go on
             | to take at least some undergrad courses, with those in the
             | 140 's range being mathematical logic gems with no real
             | counterpart in the graduate department.
             | 
             | [1]Students from Math 55 will have covered in 55 the
             | material of Math 122 and Math 113. If you have taken 55,
             | you should look first at Math 114, Math 123 and the Math
             | 131-132 sequence. https://legacy-
             | www.math.harvard.edu/pamphlets/courses.html
        
               | dwohnitmok wrote:
               | I wonder if the pamphlet's changed or I'm misremembering.
               | I distinctly remember Math 123 and Math 114 both
               | explicitly excluding Math 55 (It's also worth stating
               | that Math 122 and Math 113 are definitely not freshman
               | courses). But regardless I'd be very surprised to learn a
               | Math 55 student took Math 114 or Math 123. I would also
               | be surprised (although less so) to learn of a Math 55
               | student in the 130 series.
               | 
               | The Math 140 series have only become more serious courses
               | in the last 10 - 15 years or so IIRC. The 240 series was
               | generally where to go for serious mathematical logic
               | courses (and generally is where you would go after e.g. a
               | first 140 series course in set theory anyways).
        
           | Koshkin wrote:
           | > _within the US_
           | 
           | All fifty states or just continental?
        
           | Siira wrote:
           | Statistics needs calculus as a prerequisite. Heck, a non-
           | introductory treatment of probabilities needs measure theory.
        
           | Bostonian wrote:
           | I wonder how much statistics someone can understand without
           | calculus. For example, how do you explain what a continuous
           | probability density function (such as the Gaussian) is
           | without calculus?
        
             | pmyteh wrote:
             | I teach introductory quantitative research methods to
             | communication undergrads, most of whom have no calculus.
             | (Which is essentially optional in the UK as it's taught at
             | A Level after most students have specialised away from
             | maths).
             | 
             | They don't seem to have a problem intuiting what a plotted
             | PDF is showing. I think that's because in some sense it can
             | be read analogously to a histogram. Of course, they don't
             | have the tools to generate or manipulate one. But that's
             | honestly not something that applied social science
             | researchers have to do often when using traditional
             | methods.
        
           | pjbeam wrote:
           | My prob and stats courses required the calc sequence (US
           | based math undergraduate).
        
           | Melatonic wrote:
           | Not sure I agree with that - you also have to take into
           | account that calculus is a requirement for many other
           | sciences. I suppose you could just of course make it a pre-
           | req for things like that but I found that in highschool
           | rarely did they go that deep. Physics becomes a hell of a lot
           | easier with basic calculus for example.
           | 
           | If anything should be dropped from a highschool level its all
           | of the insane memorization you have to do for some of the
           | lower level math classes - I found that totally useless. You
           | then learn some basic calculus and realize "I just wasted so
           | much of my life" and never need to memorize those things
           | again.
        
             | JadeNB wrote:
             | > If anything should be dropped from a highschool level its
             | all of the insane memorization you have to do for some of
             | the lower level math classes - I found that totally
             | useless. You then learn some basic calculus and realize "I
             | just wasted so much of my life" and never need to memorize
             | those things again.
             | 
             | What sort of memorizations do you have in mind that you no
             | longer need to memorize once you know calculus?
        
               | ghaff wrote:
               | Pretty much all the classic Newtonian formulae you
               | memorize in high school physics classes can be derived
               | (relatively) easily once you bring calculus in. A general
               | problem with high school classes in particular--still
               | somewhat true in certain university classes but much
               | fewer--is that there are dependencies across classes. So
               | you end up with a lot of "Memorize this thing because you
               | don't have an advanced enough background to understand
               | why $XYZ is the case."
        
               | mmmpop wrote:
               | In my high school experience, this was avoided if you had
               | the desire and aptitude to just take Honors Physics
               | instead.
               | 
               | To work around the fact that many of us were still in
               | precalc, our teacher just taught us the power rule, the
               | relationship between slopes of tangent lines, etc.,
               | without diving into the "why" of why those things worked.
               | 
               | That said, yeah maybe for the most basic of university of
               | physics the whole "derive it on the fly" strategy works,
               | I guess? But when you get to more advanced courses like
               | mechanics of materials, you'll do yourself the favor and
               | take to memorizing at least a few of the commonly used
               | equations.
        
               | p1necone wrote:
               | Knowing the basics of integration/derivation makes all
               | sorts of very common concepts in physics much more
               | intuitive - velocity, acceleration, area etc.
        
               | wizzwizz4 wrote:
               | s = ut + 1/2at2
        
             | zozbot234 wrote:
             | Calculus is also a requirement for statistics and
             | probability. You simply cannot meaningfully talk about the
             | latter without referencing the former.
        
               | wbsss4412 wrote:
               | You can certainly make significant headway with some
               | basic combinatorics and basic tables for things like the
               | normal distribution, no calculus needed. This is in fact
               | how most people currently learn statistics.
        
           | geebee wrote:
           | I'm really wary of this. House wiring would be more useful
           | than Shakespeare. That's not to knock house wiring, or
           | statistics. I'd love to know more about both.
           | 
           | But don't deny yourself an understanding of the meaning of
           | limits. Almost all mathematics before calculus leaves you
           | with a misimpression that neat formulas exist to solve
           | problems. In reality, you've learned to draw straight lines
           | with a ruler, and maybe a few curves with a compass. Before
           | Calculus, you might actually believe that numbers that can be
           | expressed as the ratio of two integers are typical, and that
           | numbers like pi and the square root of two are "irrational"
           | rarities (and until calculus, you probably don't know about
           | Euler's constant unless it was introduced in precalc as
           | another one of those odd and rare numbers).
           | 
           | Look out at nature, where are the triangles, rectangles, and
           | circles? Maybe a wasp nest? Nah, not really. Try to draw a
           | cloud, a tree, a tiger, or a human face. How useful is that
           | straight line or compass? How useful is a line at all, other
           | than to hint at something you can't actually draw, maybe by
           | implying it exists as an ever vanishing limit from above and
           | below? Math required calculus the instant humans decided to
           | describe the world as it is, rather than by the limits of
           | what we impose on it.
           | 
           | Also - in stats, how do you know what the area is under the
           | probability density function?
        
             | SamReidHughes wrote:
             | Well, AP statistics covered the area under a probability
             | distribution function and people seemed to understand that
             | -- you look up the answer in a table (or use the TI-83
             | function). Presumably they'd do the same for a cumulative
             | distribution function.
        
           | jll29 wrote:
           | Calculus and linear algebra seem to _totally_ dominate the
           | curriculum in most (all?) countrie.
           | 
           | What about meta-mathematics? Topology? Logics? History of
           | mathematics? Philosophy of mathematics? Combinatorics? Number
           | theory? Discrete mathematics? Graph theory? In the post, the
           | fieds under "electives" are by far the most interesting ones,
           | IMHO.
           | 
           | And I fully agree, in-depth knowledge of probability theory
           | as well as descriptive statistics and of course the
           | application to systematic and sound decision making is
           | absolute key, and ought to be taught to anyone from medic to
           | policy makers (scary: Gigerenzer showed that medics tend to
           | be confused about the difference between P(A|B) and P(B|A) -
           | the very people whose job it is to diagnose whether you have
           | cancer or not!).
        
             | edflsafoiewq wrote:
             | Calculus and linear algebra continue to dominate in applied
             | mathematics. "How can I turn this into a problem in linear
             | algebra?" is probably the most fruitful mathematical
             | technique that has ever existed.
        
               | JadeNB wrote:
               | > "How can I turn this into a problem in linear algebra?"
               | is probably the most fruitful mathematical technique that
               | has ever existed.
               | 
               | And, from that perspective (with which I agree), calculus
               | itself is just another instance of trying to turn a non-
               | linear problem into a problem in linear algebra!
        
               | Koshkin wrote:
               | True: the differential at a point is a linear map; the
               | integral is a linear form (on the vector space of
               | functions).
        
             | ghaff wrote:
             | Interestingly the ascent of linear algebra is a
             | _relatively_ recent thing. I have an engineering degree but
             | while I was certainly exposed to basic matrix stuff, never
             | took a linear algebra class. When I was an undergrad, you
             | took differential equations in addition to basic calculus
             | for engineering. (You needed for system dynamics among
             | other things but it was very cookbook.)
             | 
             | Linear algebra became a lot more interesting once you had
             | cheap computers and Matlab.
        
             | eftychis wrote:
             | Anything besides a cursory layperson's outlook on a lot of
             | these topics (besides basic logic and history/philosophy of
             | math -- although not sure how you would teach the last
             | two/what you have in mind as curriculum) requires calculus
             | and/or linear algebra. There is a reason they say you can
             | never learn too much linear algebra.
             | 
             | And yes probability and statistics are fundamental. I was
             | shocked a bit when I learned it was not taught in
             | highschools world wide (i.e. not in the U.S.A.). But then
             | again I had gotten numb with the current average level in
             | the taught topics people arrive at undergrad at.
             | 
             | Note there is a lot of interconnectivity. To understand a
             | new concept you might need concepts in another. E.g. number
             | theory and probability.
        
             | dwohnitmok wrote:
             | > meta-mathematics? Topology? Logics? History of
             | mathematics? Philosophy of mathematics? Combinatorics?
             | Number theory? Discrete mathematics? Graph theory?
             | 
             | Honestly all of those feel more niche than calculus. I
             | agree with you and joatmon-snoo on the usefulness of
             | statistics and would probably support bumping calculus in
             | favor of statistics, but meta-mathematics, topology, logic
             | (which bleeds into meta-mathematics), combinatorics (which
             | is kind of covered by stats), number theory, discrete
             | mathematics, and graph theory are all much less useful even
             | in adjacent STEM fields (discrete mathematics and graph
             | theory matter more in CS, but far less for day-to-day
             | programming). History of mathematics is effectively an
             | entirely separate discipline and philosophy of mathematics
             | has meta-mathematics/mathematical logic as a prerequisite.
             | 
             | Calculus unlocks much of physics and engineering (and lots
             | of stats!). Large cardinal theory does not unlock any other
             | field to the best of my understanding.
        
           | staindk wrote:
           | Super agree.
           | 
           | I took calc 1 and stats 1 & 2. Much preferred the stats and
           | it set me up for understanding all kinds of science lingo in
           | articles and papers. I also indirectly use stats fairly often
           | at work.
        
             | ghaff wrote:
             | There are different types of stats. I took a stats course
             | in my grad engineering program. Not being the best person
             | at math I think I probably struggled with the math
             | sufficiently to get distracted from the concepts. When I
             | breezed through a stats course when getting an MBA I
             | understood the concepts much better--though the professor
             | was almost certainly better as well.
        
           | dhosek wrote:
           | Or the math covered in finite math classes which is a mix of
           | combinatorics, stats, probability and linear algebra. I
           | remember doing my time in the math tutorial room during my
           | grad school days and helping the kids from the business calc
           | classes who were learning math they weren't going to use from
           | books written by people who didn't understand the domain that
           | they were trying to teach math for. Seriously, what business
           | use is there for f(x) = x^1.3 or the indefinite integral
           | thereof?
        
             | ghaff wrote:
             | When I tutored in business school--mostly related to math-
             | related things (which itself says something about the level
             | of math knowledge among those who weren't engineering
             | undergrads)--pretty much the only calculus that came into
             | play was finding maxima and minima of curves in economics
             | which was both simple differentials and mostly pretty
             | academic anyway. A little later I did some more complex
             | optimization problems but that was done by software (LINDO
             | at the time) anyway.
        
         | hardwaregeek wrote:
         | I dunno, at that point, are you really doing math? Math is
         | proof. Now, granted, nobody expects you to know exactly how
         | everything is proved. But there is an expectation that you can
         | prove most of the stuff. Otherwise, it's very easy to stray
         | from the truth into the plausible-sounding, but incorrect.
         | 
         | That said, you're absolutely correct that more justification
         | and motivation is important. So much of math can be taught with
         | problems from physics, computer science, etc. Perhaps a good
         | book for you would be Concrete Mathematics by Knuth? I haven't
         | read it but people swear by it.
        
         | cptaj wrote:
         | I just want a place I can go to weekly for 15min to practice
         | math. It keeps track of what I know and gives me exercises of
         | stuff so I can retain the skills.
         | 
         | I've forgotten 90% of the math stuff I learned
        
           | robotresearcher wrote:
           | How about a textbook? At 15 mins a week, a couple of books
           | would last a year.
        
           | Buttons840 wrote:
           | Khan Academy. Finish a course, retake the course exam once a
           | year afterwards, fill in knowledge gaps as needed. Doing this
           | should keep all undergraduate math fresh in your mind.
        
         | Siira wrote:
         | The proofs can help immensely in remembering theorems and
         | knowing their needed assumptions and application area.
         | Mainstream math education is also already light on difficult
         | proofs in introductory (undergraduate) texts. You can always
         | skip the proofs anyhow.
        
         | Jach wrote:
         | Yes, all tracks of math involve people using math. Proof
         | writing is a part of use for a lot of it. There are also very
         | many tools within the use of proof writing where a lot of
         | education is around learning a bunch of tools so that you can
         | better "recognize which tool to apply, then apply tool", in a
         | future real-world use where you want or need to prove
         | something.
         | 
         | I'm a little snarky, but you have a broken idea of what math
         | is. It's not even your fault. I don't even claim an unbroken
         | idea for myself, I went through public education too, though I
         | do think it's less broken. Somehow compulsory education has
         | managed to get near universal basic literacy, but seems to have
         | failed on whatever equivalent some sibling comments have hinted
         | at exists for math or at least mathematical reasoning. A lot of
         | algebra work taught for junior high can be understood as just a
         | foundation to be able to understand later things (though you
         | can of course use some of it directly as taught without having
         | to learn more for every-day things like some boy scouting
         | activities, or helping with putting together a garden or a
         | fence, or programming). But instead of pushing algebra even
         | earlier, states are instead moving to push it even later. (Let
         | alone trying to spread awareness of even a hint of the subtle
         | divide between more general algebra and analysis that a lot of
         | STEM undergrads don't even really get a whiff of except maybe
         | knowing it's often said to be a thing.)
         | 
         | To try and be more helpful, I'll suggest you don't actually
         | want to learn math at all. So don't! At least, not directly.
         | Instead, find something you want to learn more about in
         | science, engineering, or technology/programming, and dig into
         | it until you start hitting the math being used. For many
         | things, especially at the introductory level, it's
         | fundamentally no more complicated than being able to read a
         | junior-high-school level equation. Occasionally you'll need to
         | know about some functions like square root, or sine, or
         | exponentiation, or some other new functions that will be
         | explained (like a dot product) in terms of those things. When
         | you don't understand something, you may need to find an outside
         | reference (or a few) for it, if the book itself doesn't cover
         | it enough or to your liking. Even then, you can often find
         | outside presentations of that thing which are still motivated
         | by the general field and are thus not proof-heavy.
         | 
         | However sometimes the best explanation may still be found in a
         | "pure" book just about the thing, and if you can get over
         | whatever problem you have with proofs you can learn to see how
         | they can be used to build your understanding of the thing in
         | smaller pieces, not just as tools to say whether this or that
         | is true or false. In other words, proofs can serve the same
         | function as repetitive problem-solving exercises, and are often
         | given as exercises for that reason.
         | 
         | I'm a fan of the _Schaum 's Outlines_ series of books just for
         | the sheer amount of exercises available in them, I just wish I
         | had better self-discipline to actually do more exercises.
         | Though they maybe aren't the best resources for a brand-new
         | introduction to something.
         | 
         | To give a small example, maybe you're interested in game
         | programming, and eventually want to dive into studying 2D
         | collision detection more specifically so you can implement it
         | yourself instead of using someone else's library, so you might
         | stumble on a copy of "2D Game Collision Detection: An
         | introduction to clashing geometry in games". Its explanation of
         | the dot product comes early (its whole first chapter is on
         | basic 2D vectors), consisting of 2 diagrams and two code
         | examples (the first mostly defining dot_product(), the second
         | using it as part of a new enclosed_angle() function) and some
         | text all over 2.5 pages. It gives things in programming
         | notation instead of mathematical notation, apart from some 2
         | squared symbols occasionally. It gives a few equivalences like
         | a vector's dot product with itself is its length squared, shown
         | as dot_product(v, v) = v.x2 + v.y2 = length2, without proving
         | them, and points you to wikipedia of all places if you want to
         | know more about how that or another detail are true. Why learn
         | it? It's used immediately after in explaining projection, and
         | then later in collision detection functions. Generally that
         | book is structured as: learn the bare minimum of vectors, use
         | them to implement collision detection for lines, circles, and
         | rectangles.
         | 
         | I'm not saying this is a great book but it's representative of
         | what you'll find that I think you're really after, which is
         | motivated use of some bits of math. If you don't like that
         | book's treatment of vectors, there are a billion other game
         | programming books that cover the same thing as a sub-detail of
         | their main topic, and maybe even better for you because it'd be
         | grounded in e.g. a graphical application you've already got
         | setup and running to see results rather than a standalone
         | library. Or there's special dedicated math books like
         | "Essential Mathematics for Games and Interactive Applications".
         | Or you can go find dedicated "pure math" books on linear
         | algebra if you want. Or maybe your junior high / high school
         | math education was good enough you can more or less skip most
         | of this and move on to something more interesting, like
         | physically based rendering (https://www.pbr-book.org/) which
         | _also_ of course has vectors and dot products with brief
         | explanations. Or maybe you don 't care at all about game
         | programming, and want to learn about chemical engineering, or
         | economics, or the mechanics of strength and why things don't
         | fall down, or...
        
         | narrator wrote:
         | If you just want to learn math for purely practical reasons,
         | Khan Academy (http://www.khanacademy.org) is great. It might
         | have added more lessons, but when I went through it, it went up
         | through 1st year college calculus.
         | 
         | The thing that makes it VASTLY better than most self study math
         | programs or books is that there are hundreds of exercises that
         | you can do, and see if you got the right answer. If you didn't,
         | it will in most cases explain how to do the problem so you can
         | try again with a completely different problem, so you're not
         | just memorizing the answers.
         | 
         | Another thing that makes it great is you can do a little bit a
         | day, start and stop, and come back to it and it will remember
         | your progress and where you left off.
         | 
         | Khan is also a gifted teacher. Unlike a lot of math teachers,
         | he has great pronunciation and handwriting and you can watch
         | his lessons as many times as needed.
        
           | macrolime wrote:
           | Where are there exercises?
           | 
           | I just tried clicking on some linear algebra topic, but it
           | seems there are just videos
           | 
           | https://www.khanacademy.org/math/linear-algebra/alternate-
           | ba...
        
         | LolWolf wrote:
         | Sure, here's a fun one !
         | 
         | https://web.stanford.edu/~boyd/vmls/
         | 
         | (I'd even replace Strang's "linear algebra" recommendation with
         | this book.) Imo, proofs are useful in so far as they are
         | enlightening (e.g., the proof that a problem has a minimum is
         | often useful in so far as it tells you how to solve it!) but in
         | many cases they are less so.
         | 
         | Math is pretty fun, though, proofs and all, and I'd recommend
         | trying your hand at it as a cool little side hobby! It can
         | often help with "clarity of thought" :) (In many cases, proofs
         | are just one or two lines that tell you something interesting,
         | too, not page-long arguments that are mostly definitions
         | chasing.)
        
         | Koshkin wrote:
         | > _" math for people who just want to use it"_
         | 
         | It's called "engineering mathematics." (The books by Stroud
         | would be an excellent choice here.)
        
         | susanrigetti wrote:
         | If you have a solid background in calculus, I'd recommend
         | Zill's Advanced Engineering Mathematics, which is pretty much
         | basic math for physicists and engineers (aka for people who
         | need to "use it").
        
           | brimble wrote:
           | Heh, I have a long-forgotten-due-to-complete-lack-of-use-
           | for-15-years-straight background in calculus. Solid, it is
           | not. Thanks for the tip, though.
        
             | susanrigetti wrote:
             | In that case, I recommend starting out with Zill's
             | Precalculus with Calculus Previews and then working through
             | Stewart's Calculus: Early Transcendentals!
        
               | brimble wrote:
               | I'll check those out, thank you!
        
         | jackallis wrote:
         | i second this. there should clear distinction between academic
         | math and "real world usage" math.
        
           | psyklic wrote:
           | Having a deep (proof-based) understanding leads to more "real
           | world" insights. So, there may not be a clear distinction.
        
           | Koshkin wrote:
           | But the distinction is generally not as clear as you may
           | think. (1) Much of the mathematics came from real world
           | problems (so, in particular, one may get drawn into some kind
           | of mathematical research and even end up discovering new
           | mathematical facts). (2) Sometimes when applying mathematics
           | one still needs to employ deduction (derive a formula, prove
           | a statement one wants to rely on, etc.).
        
         | joe_the_user wrote:
         | Math education has become torturously miserable in the US by
         | moving extraordinarily slowly. You have multiple years of
         | working on only slightly more complex equations and concepts
         | and naturally people get sick of it.
         | 
         | You have generations of teachers who barely know math and view
         | it as a punishment, teaching kids and instilling the same views
         | in them.
         | 
         | And then you have outside still saying "can't we have condense
         | it and simplify it further so we won't have to learn all these
         | useless abstractions" and the curriculum bends further this
         | way. But these actual situation of math is that not
         | understanding what's happening is the thing makes it an empty
         | and unpleasant activity.
         | 
         | Edit: Also, yeah, 90%-99% of math can be accomplished with some
         | math software. It's just for the remain small percentage of
         | stuff you need some understanding and for a small percentage of
         | that you need lots of understanding. So most of this seems
         | useless but 99% correct is actually not enough in some
         | significant number of technical situations, etc.
        
         | pphysch wrote:
         | > Are there any "math for people who just want to use it"
         | tracks in math pedagogy?
         | 
         | Use it for _what_? That is the question. If you pursue the
         | _what_ , you will inevitably be exposed to genuine ways that
         | mathematics may be employed by it.
         | 
         | The academic standard for "learning math" is like "learning
         | programming" by reading the C++ language/STL spec from front to
         | back. No one productively learns programming that way, and even
         | if someone did, they would hardly be well off when faced with a
         | real-world production C++ codebase that follows $BIGCORP's
         | inhouse programming style.
        
           | vharuck wrote:
           | I agree. If anyone wants to study "math in practice," they
           | should pick a science or engineering track they like. Math
           | will be included.
        
         | dwrodri wrote:
         | Swinging by to plug my personal favorite resource for
         | refreshing my self on Bayesian stats:
         | https://www.youtube.com/playlist?list=PLwJRxp3blEvZ8AKMXOy0f...
         | 
         | I think statistics is by and large the most proportionally
         | underrated subject proportional to its utility. A good command
         | of stats and probability expands your power to use data to
         | reason about answering questions. The channel author, Ben
         | Lambert, has an alternative playlist where he uses some of the
         | techniques taught in this playlist to solve problems in
         | econometrics. However, a lot of what is taught here builds a
         | great foundation for other domains, on everything from
         | bioethics to data journalism to computer vision.
         | 
         | Another great channel that focuses a bit more on the machine
         | learning side of things is StatQuest with Josh Starmer:
         | https://www.youtube.com/c/joshstarmer
        
         | k__ wrote:
         | I think, the problem is, proofs are what makes math useful.
         | 
         | This might sound a bit dense, but the alternative is what 90%
         | of programmers do every day.
        
           | Koshkin wrote:
           | I think one can get far enough by applying known mathematical
           | facts. (Proof: elementary school math is useful.)
        
             | auggierose wrote:
             | The problem is, usually you need to combine known
             | mathematical facts to solve a problem. Now, how do you know
             | that you combined them properly?
             | 
             | Yup. You need to know what a proof is.
        
         | eftychis wrote:
         | Well you can think of it like going to the gym. You don't
         | exactly see people doing squats during their daily life, but
         | you can see the results of people having a good physical core.
         | 
         | This needs to be explained further during education and
         | motivated appropriately. We have a short-term utilitarian
         | perspective, and we need to take a step back at times and
         | recall that it takes time and lots of sculpting to transform a
         | wood log to a art piece.
         | 
         | As you can jog everyday for fun and/or for the challenge you
         | can also jog to improve your physical health. And not doing
         | proofs is like declaring a guy can weight-lift by just watching
         | videos on youtube and never lifting a weight. Or a guy can
         | "code" without writing a line of code.
        
         | konschubert wrote:
         | You don't need proofs, but you still need an intuition for why
         | things work the way they do.
         | 
         | Otherwise you will be lost as soon as you leave the textbook
         | territory.
         | 
         | Proofs are just one way to build intuition.
         | 
         | The best way to learn applied maths and get intuition is an
         | "Introduction to Maths for Physicists" 101 course.
        
         | helpfulclippy wrote:
         | I did a degree in applied math. You'd think this would be "math
         | you'll use," but the fact is that despite my program having a
         | CS concentration, most of the stuff I did was not really
         | applicable in practice.
         | 
         | However, one thing that has been VERY applicable is
         | proofwriting. Although math proofs are far more rigorous than
         | most real world stuff, the discipline I learned in writing
         | proofs has carried over into pretty much everything from
         | programming (will this algorithm work every time?) to executive
         | decisions (why, specifically, should we believe X?). Obviously
         | in the former case I wind up doing actual proofs, and in the
         | latter I make strong arguments based on logical consequences of
         | established or presumed facts, or find flaws or gaps in
         | arguments that are being considered.
         | 
         | I really wish I'd spent a lot more time on proofwriting than
         | say, vector calculus.
         | 
         | Of course you may want specific math to solve real problems,
         | and that's a real need too! Not to diminish your point at all,
         | just advocating for proofs to be seen in a practical light.
        
           | auggierose wrote:
           | Proofs are indeed very practical. For example, I believe
           | Leslie Lamport mentioned somewhere that he only came up with
           | the final version of Paxos once he tried to prove it, and
           | noticed that some condition he assumed wasn't necessary at
           | all.
        
             | dhosek wrote:
             | The reasoning behind having geometry be the standard high
             | school sophomore math class is that that's the age where
             | kids would be ready to do proofs. Except that curriculum
             | designers seem to have forgotten this and except in honors
             | classes, most sophomores don't get taught proofs in
             | geometry and instead get a set of inert rules about shapes
             | that they have no use for.
        
               | whatshisface wrote:
               | Geometry uses a deduction-only basket of proof techniques
               | that don't prepare students for proofs done afterwards. I
               | would like to see it replaced by elementary number theory
               | which naturally uses a lot of induction/recursion and has
               | some uses for proof by contradiction.
        
               | auggierose wrote:
               | Geometry has really all that is needed for proofs:
               | 
               | * Axioms
               | 
               | * Substitution
               | 
               | * Modus Ponens
               | 
               | * Universal Quantification
               | 
               | Induction or proof by contradiction are just special
               | cases of this.
               | 
               | But yeah, geometry for introducing proofs is difficult,
               | because it is so easy to confuse visual intuition with
               | proof. At the very least, you need a capable teacher who
               | knows the difference. But nobody expects children to
               | understand it all from the get go. A healthy struggle to
               | disentangle intuition and proof, and then to entangle
               | them again later on once you know the difference, that's
               | the path to understanding mathematics.
        
               | whatshisface wrote:
               | The thing about geometry is that it does not take long
               | before you've taught those four things, and then you
               | start teaching stuff that is specific to plane geometry.
        
               | auggierose wrote:
               | There are worse things to learn than plane geometry. It's
               | actually a good thing to have a fixed topic to really
               | learn those 4 things. Because once you really understood
               | those 4 things, you are done, and you know everything
               | about proofs in general there is to know.
        
       | wanderingmind wrote:
       | No recommendation on probability. Thats strange given that the
       | author is a physicist and fundamentals of modern physics rests on
       | probability. My recommendation is the classic "Probability
       | Theory, The logic of Science by E.T.Jaynes" which is a Bayesian
       | formulation.
        
       | RoddaWallPro wrote:
       | I read a Murakami novel in high school, 1Q84. The protagonist is
       | a math teacher who talked about math in a way that I had never
       | seen before. I'd been told I was "good at math" beforehand(for
       | whatever that means, I'm not a fields medalist or anything), but
       | for ~6 months after reading that book, I was _really good_. Like,
       | suddenly I did not have to do any homework in my sr. year
       | calculus class. I loved sitting in class and watching my teacher
       | work through problems, and it seemingly imprinted directly into
       | my brain, because while doing no homework I could still ace the
       | exams while writing with a pen (no erasing and re-do'ing with a
       | pencil). All because of the way this fictional teacher from 1Q84
       | talked about math.
       | 
       | Has anyone else had an experience like that? (With math or other
       | things?)
        
       | LAC-Tech wrote:
       | I really don't.
       | 
       | For many, many years I thought I did. I'd have a brief surge of
       | interest for a few weeks, and then get completely bored of it.
       | I'm not someone who finds it inherently easy, so boredom +
       | difficulty = failure.
       | 
       | When I was foolish enough to do this in university, it meant
       | doing great in the first few assignments, and then abysmally in
       | the exam.
       | 
       | So my policy now is to never study maths for its own sake. Only
       | when there's equations in a computer science paper I don't
       | understand.
        
         | [deleted]
        
         | [deleted]
        
       | dekhn wrote:
       | I'm still stuck at "wait, sets can contain other sets, and sets
       | can contain themselves?" part of Russell's paradox, and I'm close
       | to retirement!
       | 
       | I don't want to study math. I want to know enough of it to solve
       | some well-understood problems I've wanted to solve for decades.
       | Simply learning how to diagonalize a matrix (and how to use such
       | a thing) meant more than understanding a bunch of complicated
       | matrix theory.
        
       | dr_dshiv wrote:
       | If _doing_ math is essential to conceptual understanding and
       | application, could the interface of math and physics be made more
       | human-centered? For instance, the shift from Roman numerals to
       | Arabic numerals made _doing_ math easier. Based on your
       | experience, might it be possible to increase accessibility by
       | revising some of the arcane conventions of math and physics?
       | 
       | See Brett Victor's 2011 proposal: http://worrydream.com/KillMath/
        
         | andrepd wrote:
         | Why is it that every time any subject about mathematics comes
         | up there is _always_ a complaint about notation?
         | 
         | Your link doesn't even exactly talk about notation, but about
         | pedagogy. Can you be more specific about which notation your
         | consider "arcane"?
        
         | Jach wrote:
         | My favorite accessibility-increasing tool is the computer.
         | Doing math shouldn't involve so much _circus math_ , i.e. doing
         | things just for show, since a computer does so much immediately
         | and accurately. We already use graphing calculators, but
         | there's so much more they can do, let alone actual PCs, cell
         | phones, and web apps. By chance in 9th grade "Intermediate
         | Algebra/Algebra 2" I had a teacher not wholly opposed to modern
         | technology and so he only had us do a small amount of those
         | "solve this system of equations using a 3x4 matrix by hand,
         | showing each matrix transformation to reach the row reduced
         | form, taking up some pages of paper" problems before he brought
         | in a classroom set of chonky TI-92 calculators and showed us
         | the rref() function. That Christmas I asked my mom to upgrade
         | me from my non-graphing scientific calculator that had served
         | since elementary school to a TI-89 Titanium that served me even
         | through college until I learned and got used to various PC
         | programs. The lesson that there were powerful tools around
         | stuck with me pretty fast though, and I wrote some programs on
         | the calculator for that and other classes throughout HS; in HS
         | physics I also had learned more programming and did a little
         | simulation with pygame and it was fun to enter numbers in the
         | program, run it, see the mass trajectory animate and show some
         | computed values, and then do the actual experiment and get the
         | same results.
         | 
         | I met a friend many years later who sadly was still forced to
         | do that rref()-by-hand for even larger systems of equations in
         | university! That left no time to actually learn anything useful
         | in linear algebra. Madness.
         | 
         | https://theodoregray.com/BrainRot/ has some nice ranting about
         | this (though it does go a bit off the rails when it starts
         | talking about video games).
        
       | abhisuri97 wrote:
       | As a fellow penn alum, I can totally vouch for Ghrist's approach
       | to calculus. Check out his youtube channel:
       | https://www.youtube.com/c/ProfGhristMath
        
       | cpp_frog wrote:
       | > _My goal here is to provide a roadmap for anyone interested in
       | understanding mathematics at an advanced level. Anyone that
       | follows and completes this curriculum will walk away with the
       | knowledge equivalent to an undergraduate degree in mathematics._
       | 
       | NO, NO, NO.
       | 
       | There is no real way to go up to the real deal without having
       | understood elementary Functional Analysis, which the article
       | doesn't even mention. FA is roughly what Linear Algebra would
       | look like if instead of finite dimensional vector spaces we
       | considered infinite dimensional vector spaces. It opens the
       | rigorous path to non-linear optimization, analysis of pdes,
       | numerical analysis, control theory, an so on. What this article
       | mentions is a way to work around things, but nowhere near an
       | undergraduate degree in mathematics.
       | 
       | I'm astonished that the PDE section has such books, they look
       | like the calculus aspect of partial differential equations. A
       | more appropriate book would be L. C. Evans' _Partial Differential
       | Equations_. Same with ODEs, no mention of Barreira 's or
       | Coddington & Levinson's books.
        
         | ratzkewatzke wrote:
         | I'm a fan of functional analysis, but even in my (very
         | competitive) undergraduate curriculum, it wasn't required for a
         | bachelor's in mathematics. I think Susan's guide covers most of
         | what the undergraduate programs I've seen require.
        
           | cpp_frog wrote:
           | It was for me (french school of math), that and also measure
           | theory.
        
         | davidmr wrote:
         | This is certainly not universally the case, even in very well-
         | regarded departments. The University of Chicago, for example,
         | does not require it:
         | http://collegecatalog.uchicago.edu/thecollege/mathematics/.
        
       | Mimmy wrote:
       | Going from Strang to D&F seems like a steep jump. The former is
       | an applied textbook for non-mathematicians and the latter is a
       | proof-based text for advanced undergraduate / graduate-level math
       | students.
       | 
       | I would suggest working through a proof-based linear algebra book
       | in between to ease the transition. Axler's is a good one.
       | Alternatives include Hoffman and Kunze and the more modern
       | Friedberg, Insel, and Spence.
        
         | selimthegrim wrote:
         | Strang's latest book DE&LA is disappointing, it is linear
         | algebra and its applications with the abstraction taken out and
         | mushed together with supplementary notes from ODE
         | videolectures. Mattuck's ODE course is good.
        
         | Py-o7 wrote:
         | For many years MIT students would go from Strang in year 1 to
         | Artin in year 2. Artin != D&F of course though many would say
         | it does less hand holding than D&F
        
         | susanrigetti wrote:
         | Gross's review of linear algebra from his MIT algebra course
         | bridges the gap: http://wayback.archive-
         | it.org/3671/20150528171650/https://ww.... A combination of that
         | and then chapter 11 in D&F should cover whatever readers didn't
         | get from Strang.
         | 
         | That being said, Axler is an excellent book. I don't know if I
         | would replace Strang with it, but I should add it as a
         | supplement to the next edition of this guide!
        
         | tptacek wrote:
         | Both Strang and D&F are extra-relevant for cryptography (I was
         | struck by how much the earliest parts of D&F --- which I
         | haven't gotten much further beyond --- read like the
         | mathematics background chapter of a cryptography book), and
         | I've been in study groups for both of them with non-
         | mathematicians that went OK. But the D&F study group fell apart
         | for logistical reasons, so maybe it would have hit a wall after
         | a couple more months.
        
           | pvg wrote:
           | _read like the mathematics background chapter of a
           | cryptography book_
           | 
           | A lot of maths-related books, especially ones intended as
           | textbooks will read like that in part because they aren't
           | kidding about the 'abstract' in the title - they're trying to
           | teach/re-summarize key concepts of mathematical abstraction.
           | It's a good and true thing to notice.
        
         | dwohnitmok wrote:
         | Second Axler. "Linear Algebra Done Right" is probably the pure
         | mathematics textbook I've most enjoyed reading ever (but be
         | warned you will learn very little about applied methods from it
         | if that's what you care about).
         | 
         | Also enjoyed Artin's Algebra.
        
           | musgravepeter wrote:
           | +1 for Artin's Algebra. I think is very under appreciated.
        
           | cgriswald wrote:
           | My university course in linear algebra taught me how to
           | manipulate matrices. It was super uninteresting, and easy. I
           | aced every test, but got a B in the course, because the
           | professor assigned an asinine amount of homework (that I
           | either aced or didn't do), perhaps holding the article
           | author's view that:
           | 
           | > solving problems is the only way to understand mathematics.
           | There's no way around it.
           | 
           | ...without also understanding that doing problems is not a
           | substitute for understanding.
           | 
           | (I'm still salty about that course. I've been doing linear
           | algebra based puzzles _nearly every day of my life_ and this
           | professor somehow made the topic a boring chore.)
           | 
           | I complained about this to a friend who had also taken the
           | course and he turned me on to Axler. I read through the first
           | chapter, nodding along as I went. I got to the problem
           | questions and couldn't believe what Axler was asking was even
           | related to the material I had read through. I really
           | struggled at first to understand. Axler was heavily
           | juxtaposed to my previous experience. However, when I did
           | understand, I didn't just understand, I _grokked_.
           | 
           | It was just such an awesome experience, and I credit that
           | book in particular with breaking me out of a mathematics
           | plateau and with liberating my mathematics education from a
           | strict reliance on academia. The text is almost magical.
        
             | dwohnitmok wrote:
             | > I got to the problem questions and couldn't believe what
             | Axler was asking was even related to the material I had
             | read through.
             | 
             | I think this is a common first experience when first
             | hitting pure mathematics. Mathematics often feels like very
             | rote applications of rules drilled into one's mind, and
             | then you hit a pure mathematics textbook and the questions
             | become a step change in difficulty where you're expected to
             | derive novel insights on your own that the text doesn't
             | hold your hand in showing. A single problem can easily
             | occupy days of your time before the "aha!" moment, but as
             | you say, once you get the "aha!" you realize your
             | understanding is quite profound as opposed to a shallower
             | understanding of just how to apply a given set of rules.
        
         | selimthegrim wrote:
         | I have been using Morris in my class.
        
       | nyc111 wrote:
       | I don't agree with this article, it as off-putting as the usual
       | math eduacation it criticizes. I wonder how one can propose a
       | curriculum to study math and not mention Euclid. One learns more
       | mathematics from this article https://mathshistory.st-
       | andrews.ac.uk/Extras/Russell_Euclid/ by B. Russell where he
       | harshly criticizes Euclid than 2 years of calculus. Newton did
       | not know calculus but he knew Euclid's Book 5, the book about
       | ratios and proportions. Euclid's 5th Book must be the starting
       | point for the study of math. When we say "math is the language of
       | nature" we really mean that nature is proportional. Ratios and
       | proportions are fundamental.
        
       | ouid wrote:
       | If you actually want to study math, you probably shouldn't touch
       | calculus until you've take linear algebra and a fair amount of
       | topology, since these are the two structures on sets that
       | (differential) calculus is founded upon.
       | 
       | For other subjects, you can briefly substitute an intuition for
       | the underlying structures with sufficient finesse in the
       | presentation of the material (see the theory of knots and links,
       | for an example), but calculus is not, in my experience, such a
       | subject, and the early emphasis on it is harmful for the study of
       | _mathematics_ , which is supposedly what your list is for.
       | 
       | For some reason this is heresy, but I have honestly no idea how
       | you are supposed to appreciate calculus from a mathematical
       | perspective without being able to define the large stack of terms
       | that constitute it. The situation is potentially different for a
       | physicist, but if you want to study mathematics, the physical
       | world is not the object of study, rather it is precisely the
       | definitions that we have chosen.
        
       | pattt wrote:
       | Spivak's Calculus reignited my interest and appreciation in math.
       | Sad to discover the author passed away quite recently. The way of
       | explaining principles and making you do the hard work via
       | problems which I believe is a must with this book, is profoundly
       | astonishing. There's a lot of mathematical insight packed into
       | those problems, it almost feels you can build up the entire high
       | school and the early uni curriculum from the ground up, for
       | instance there are a number of popular formulas you'd arrive at
       | and derive accidentally while working on those problems.
       | Furthermore it really works your brains by making sure you can
       | reason within the established framework and exercise great doubt.
       | I'm taking this book very slowly.
        
       | mathgenius wrote:
       | Modern calculus (analysis) was invented because people shot
       | themselves in the foot working with topology and wondering
       | exactly what is a "curve" ? I am a big fan of this approach to
       | learning mathematics, just forge ahead and when (if) things fall
       | apart then go back and fix up the foundations. To this end I
       | recommend a couple of books. "The Knot Book" by Adams is a very
       | interesting exploration in topology (without requiring all the
       | years of study at university before you are allowed to learn
       | exactly what a topology is). And in another direction, group
       | theory was invented because the study of symmetry gets very
       | tricky! But if you want to dive in anyway then have a look at
       | Conway's "The symmetries of things". It is a lot of fun. Most
       | modern group theory (or algebra) books don't actually have any
       | pictures of symmetric things, just endless formulas and lemmas.
       | If you want to be a pro, then you gotta learn that stuff, but
       | there's definitely pathways into higher mathematics that don't
       | require you to learn that.
        
         | PartiallyTyped wrote:
         | Speaking of group theory, I can recommend "A book of abstract
         | algebra". I think that it's a very approachable introduction to
         | the topic. As a person with a CS degree doing ML, it changed my
         | perspective on so many different topics, I can't recommend it
         | enough.
         | 
         | https://www.goodreads.com/book/show/8295305-a-book-of-abstra...
        
       | daxfohl wrote:
       | I loved last year being able to take university courses online. I
       | knocked out analysis, topology, and quantum mechanics as a non
       | matriculated student. I'd had those books for years but never
       | could get through them alone. (The main thing being, you really
       | don't have anything to gague whether you know it well enough or
       | not).
       | 
       | I really wish there was more opportunity for that. I'd love to
       | take a few more classes, mostly in pure math, but there's simply
       | nothing on offer for remote study past the 200ish level. (There
       | are some remote masters programs in applied math, but nothing for
       | pure).
       | 
       | I don't think I'd enjoy doing a PhD full-time. One or two classes
       | per semester while working seems just about right. But the
       | closest university is an hour away, so in-person isn't a
       | realistic option.
        
         | elteto wrote:
         | Where did you take your classes?
        
           | daxfohl wrote:
           | University of Washington
        
         | adamsmith143 wrote:
         | Texas AM has a program that gets somewhat close though it
         | definitely has a computational focus. Here's a list of their
         | recently offered courses:
         | https://www.math.tamu.edu/graduate/distance/openletter.html
        
       | itcrowd wrote:
       | Susan, I greatly appreciate this list and will definitely come
       | back to use it as a reference if I need a book recommendation. (I
       | don't think I'm the target audience, although who knows what the
       | future brings..)
       | 
       | That being said, I think you are missing out on an opportunity to
       | reach a wider audience. It bugs me a bit that the requirements
       | seem very American-centric. What I mean is the following bit:
       | 
       | > A high school education -- which should include pre-algebra,
       | algebra 1, geometry, algebra 2, and trigonometry -- is
       | sufficient.
       | 
       | And later the paragraph on "pre-calculus".
       | 
       | I know that many places don't have such names for courses in high
       | school. In fact, often it's just called "Mathematics" and you
       | either take it or you don't (obviously there is a spectrum here).
       | 
       | How is a prospective (non-American) student to know what is
       | covered in Algebra 2 in an American high school?
       | 
       | I'm not asking you to change the article, I just hope I can nudge
       | you into realizing that the text as it is now is more difficult
       | than it needs to be for non-Americans.
        
         | jerry1979 wrote:
         | Do we have good universal descriptors for math levels? I'm a
         | big fan of accessibility, and I think your idea about tweaking
         | language to reach a wider audience could be a big win for
         | increasing the article's impact.
         | 
         | To update the article to include your recommendations, the
         | author would probably need some kind of "cross-walk" which
         | would map the American perspective to a more universally
         | understood framework. Would you happen to know what "pre-
         | calculus's" opposite number would be in the universal
         | framework?
        
       | rongenre wrote:
       | I have a decades-old math degree and ended up working in tech as
       | an engineer. Are there options, like a "Math Camp for the Middle-
       | aged" where I could get a chance to re-learn everything I've
       | forgotten?
        
       | paulpauper wrote:
       | You can get good or better at something with effort, but few will
       | ever make to leap to being great or world class at it, no matter
       | how hard they try.
        
         | atan2 wrote:
         | True! But sometikes getting better at something is all people
         | really want, and that's ok. I see that most of my CS students
         | just want to be able to not see math as an obstacle when
         | learning new/interesting things.
        
       | fjfaase wrote:
       | I am bit surprised there is nothing about graph theory in there.
       | Also nothing about combinatorics or knot theory to mention two
       | other subjects. If you want to make people dive into mathematics,
       | it might be a good idea to show a broad range of subjects instead
       | of focusing on the traditional subjects.
        
         | travisjungroth wrote:
         | It's amazing how different the subjects of mathematics are.
         | It's like the difference between a drum and flute.
         | 
         | You listed some of my favorite stuff. Weirdly, when I was 11,
         | my math tutor told me I'd probably really like finite
         | mathematics. She turned out to be right.
        
           | Someone wrote:
           | > It's amazing how different the subjects of mathematics are.
           | It's like the difference between a drum and flute.
           | 
           | I think it's amazing how _connected_ the fields are. It's
           | almost like "pick any two of analysis, algebra, geometry,
           | number theory, topology, turn one into a adjective and you've
           | got a new subject area".
           | 
           | Topological algebra? Check
           | (https://en.wikipedia.org/wiki/Topological_algebra)
           | 
           | Algebraic topology? Check
           | (https://en.wikipedia.org/wiki/Algebraic_topology).
           | 
           | Geometric topology? Check
           | (https://en.wikipedia.org/wiki/Geometric_topology).
           | 
           | Geometric algebra? Check
           | (https://en.wikipedia.org/wiki/Geometric_algebra)
           | 
           | Algebraic geometry? Check
           | (https://en.wikipedia.org/wiki/Algebraic_geometry)
           | 
           | Geometric number theory? Close
           | (https://en.wikipedia.org/wiki/Geometry_of_numbers)
           | 
           | Mix algebra, number theory, and topology, and you may end up
           | with arithmetic topology
           | (https://en.wikipedia.org/wiki/Arithmetic_topology)
           | 
           | And don't confuse that with arithmetic geometry
           | (https://en.wikipedia.org/wiki/Arithmetic_geometry)
        
             | sdenton4 wrote:
             | You can add 'combinatorics' to the list of primitives.
             | 
             | Algebraic combinatorics (imo) encompasses related
             | structures in all three of combinatorics, algebra, and
             | geometry, though.
        
       | Buttons840 wrote:
       | Where's statistics? You mean to tell me I could go through all
       | that and come out not knowing statistics?
        
         | Koshkin wrote:
         | Agree, but I have a feeling that statistics is more like
         | (theoretical) physics, in the sense that it is "not math."
        
           | Buttons840 wrote:
           | Yeah, it's more application oriented and philosophical than
           | the pure calculation of pure math. I think it's under-taught
           | in schools though. I think it's more useful than calculus for
           | most people and should be taught before it.
        
       | ghufran_syed wrote:
       | I went from only having done high school math 10 years ago to
       | completing an MS in math and statistics at my local state
       | university while working in an unrelated field. I would recommend
       | NOT starting with calculus if you haven't done it, instead, just
       | learn how to do proofs - I used Chartrand "Mathematical proofs" -
       | You don't need to know any math beyond algebra in order to do
       | that most of this book. If you need to revise or learn Algebra,
       | then I would do Stroud "engineering math" first which is designed
       | for self-learners with lots of solutions and feedback.
       | 
       | At some point, it would be good to get a a copy of Lyx and start
       | to learn to write math in LaTeX - Then you can get feedback on
       | your proofs online at math.stackexchange.com if you don't know
       | any math people locally.
       | 
       | Feel free to get in touch with me if you want to discuss further,
       | happy to help!
        
         | criddell wrote:
         | I looked up the Chartrand _Mathematical Proofs_ book and it 's
         | been a while since I had to buy a textbook, but $175 for
         | hardcover and $75 for paperback or ebook? That's nuts. If I
         | were a student today, I'd pirate that and feel absolutely no
         | remorse for doing so.
        
         | joe_the_user wrote:
         | Well,
         | 
         | I feel think one can get a bunch of "Really you should start
         | with X" statements concerning math. _Really_ you should start
         | with proofs, _really_ you should start with problems, _really_
         | you should start with these concepts. I started with concepts
         | rather than proofs or problem and I too went to a MA and
         | various study. I tackled both proofs and problems but I don 't
         | think I'd have done as well if I'd jumped on these immediately.
         | 
         | So, altogether for someone wanting to get into advanced math,
         | I'd say to look at the variety of advice out there and follow
         | the kind that seems to help your progress.
        
       | hintymad wrote:
       | I find it hard to believe that the author started to appreciate
       | physics by reading The Feynman Lectures on Physics before any
       | exposure to physics or even algebra, and in less than three years
       | went from barely knowing high school math to enjoying advanced
       | mathematical physics and graduate-level quantum physics. It looks
       | this is one-in-a-million level brilliance as learning the sheer
       | amount of requirement knowledge in such a short time is amazingly
       | challenging: analysis, functional analysis, complex analysis,
       | linear algebra, abstract algebra, differential equations,
       | mathematical statistics, and all the physics: mechanics,
       | electromagnetism, thermodynamics, optics, statistical mechanics,
       | relativity, and of course quantum physics, all in less than three
       | years.
       | 
       | Kudos if the author is this talented.
        
         | whatshisface wrote:
         | I agree that this does not on its surface seem possible, but I
         | can think of a few explanations.
         | 
         | 1. I recently spent a week on one section of one chapter of a
         | math book. I was able to follow it within an hour on the level
         | of "these are the rules and this is the sequence of their
         | application," but I have stuck with it since then because I
         | wanted to understand it well enough that the proof they chose
         | to use would seem obvious to me. If you saw "understanding
         | math" like the peak of a mountain, you'd get there a lot more
         | quickly, but if you want to try out every permutation of every
         | device and condition anything can take forever.
         | 
         | 2. Algebra seems simple in retrospect, and my teenage self was
         | kind of dumb. Maybe with my complete adult brain I'd be able to
         | finish highschool starting from scratch in a few months.
         | Evidence to that point is the pacing of college remedial math
         | classes. Maybe, to a certain extent, people have an innate math
         | setpoint that they will snap to very quickly when given the
         | chance.
         | 
         | 3. Intelligence is equally distributed between genders, but
         | most professional physicists are men, which means that for
         | every professor there is almost exactly one corresponding woman
         | who has equal potential but isn't in the system. If you heard
         | that the department chair at a university sat down and read a
         | book about topology without a lot of trouble you wouldn't be
         | surprised at all. In other words, it's not surprising that
         | someone can do this, it's surprising that someone who can do
         | this is not in the social bucket for people that do it, but if
         | you think about the other things you've heard about that, you
         | realize you already knew.
         | 
         | I am inclined towards #3 out of all these explanations but all
         | may be true at once.
        
           | paulpauper wrote:
           | women had an advantage over men in regard to memorization.
           | this helps greatly at learning.
        
           | hintymad wrote:
           | > Intelligence is equally distributed between genders, but
           | most professional physicists are men,
           | 
           | Why limit yourself to gender? Why not white vs other skin
           | color? Why not the US vs another country? Why not democrat vs
           | republicans? Why not western culture vs whatever other
           | culture? Seriously, this kind of categorization is just
           | ridiculous, especially when you speculate instead of showing
           | evidence.
           | 
           | No, I won't be surprised if a STEM professor is reading
           | topology. I will be surprised if a gender-study professor is
           | reading topology. I will be also surprised if some _stranger_
           | (i.e. I don 't know the background of this person) who could
           | only do pre-algebra in high school says Topology without
           | Tears is the _first_ book on Topology that they read and they
           | immediately fall in love with topology. Possible, for sure.
           | Surprising, of course. It 's just a matter of probability.
        
             | whatshisface wrote:
             | I'm not sure what objection is being made. We know that
             | there are lots and lots of women who could be physicists
             | but decided not to. You don't stop existing when you don't
             | get labeled, but you do start surprising people who expect
             | you to have been.
             | 
             | > _The researchers say that as last author is usually
             | associated with seniority, based on this data, their model
             | predicts that it will be 258 years before the gender ratio
             | of senior physicists comes within 5% of parity._
             | 
             | https://physicsworld.com/a/gender-gap-in-physics-amongst-
             | hig...
        
         | [deleted]
        
         | paulpauper wrote:
         | More like one in 50-100 million brilliance, and such people do
         | exist. It's a statistical certainty they exist. Terrance Tao
         | for example.
        
       | [deleted]
        
       | Py-o7 wrote:
       | This felt like it was written by a physicist or engineer.
       | 
       | Too much emphasis on differential equations and not enough on
       | things like topology, functional analysis and/or non-introductory
       | parts of algebra like say representation theory.
        
         | susanrigetti wrote:
         | guilty as charged! :)
        
           | bitexploder wrote:
           | As someone with a keen interest in learning Engineering part
           | time, I found your write ups really helpful though! I enjoy
           | learning math but like to have an angle towards a practical
           | and useful application. It keeps me a little more motivated
           | than pure math learning. With ADHD the concept of being able
           | to build cooler things always keeps me going. But somewhere
           | along the way of learning purely theoretical things for too
           | long my brain just loses interest (not enough reward), even
           | though I enjoy it in the moment it is hard to get to the
           | starting line and take the first step after a while :)
        
       | pphysch wrote:
       | IME (as a math-degree-haver) the value of mathematics is in
       | improving one's ability to mentally model and reason about
       | complicated _real-world phenomena_. A lot of folks lose sight of
       | the reality and get lost in the mysticism, especially within the
       | academic regime.
       | 
       | > [Mathematics] is the purest and most beautiful of all the
       | intellectual disciplines. It is the universal language, both of
       | human beings and of the universe itself. [...] That doesn't mean
       | it's easy -- no, mathematics is an incredibly challenging
       | discipline, and there is nothing easy or straightforward about it
       | 
       | I am always, always going to condemn this unnecessary
       | mystification and idealization of mathematics. It's exclusive and
       | misleading.
        
         | susanrigetti wrote:
         | You cut out the middle of that paragraph, which says:
         | 
         | "Sadly, there is all sorts of baggage around learning it (at
         | least in the US educational system) that is completely
         | unnecessary and awful and prevents many people from
         | experiencing the pure joy of mathematics. One of the lies I
         | have heard so many people repeat is that everyone is either a
         | "math person" or a "language person" -- such a profoundly
         | ignorant and damaging statement. Here is the truth: if you can
         | understand the structure of literature, if you can understand
         | the basic grammar of the English language or any other
         | language, then you can understand the basics of the language of
         | the universe."
         | 
         | :)
        
           | pphysch wrote:
           | I'm not sure what your point is. Are you implying that you
           | are _not_ contributing to the mystification and idealization
           | of mathematics?
           | 
           | In other words, I do not see how you are dealing with the
           | "baggage" of learning mathematics beyond name-dropping it. In
           | my opinion, the mysticism is the baggage. And then the rest
           | of the blogpost reads like a conventional curriculum within
           | the conventional academic regime with which we associate that
           | baggage.
        
             | dang wrote:
             | Please don't post in the cross-examining style. We want
             | _curious_ conversation here.
             | 
             | This is in the site guidelines:
             | https://news.ycombinator.com/newsguidelines.html.
        
               | pphysch wrote:
               | I don't follow. The author dismissively ctrl-V'd a
               | paragraph with no further explanation, and my response
               | asking for elaboration gets shadow-buried by a mod. What?
        
         | akomtu wrote:
         | On the mysticism note, I want to add that math is perhaps the
         | only subject that forces one to engage the upper "abstract"
         | mind. The lower mind is concerned with modeling real world
         | phenomenas, while the upper mind works with purely abstract
         | things, aka the "true reality" in mysticism.
        
       | cathrach wrote:
       | While I understand that the author has good intentions, I
       | strongly disagree with the general idea of this post, which is
       | that anyone can learn math through an almost entirely analysis-
       | focused curriculum while other topics like topology, game theory,
       | set theory, etc. are presented as advanced and graduate-level.
       | This is practically equivalent to saying that anyone can learn
       | history, and they should learn all about British history in
       | undergrad, and then graduate-level courses might teach you more
       | about the history of South America.
       | 
       | Some of my thoughts (mostly drawn from personal experience, feel
       | free to disagree):
       | 
       | 1. IMO "learning math" is really about learning how to recognize
       | patterns and how to generalize those patterns into useful
       | abstractions (sometimes an infinite tower of such abstractions!).
       | So it really doesn't matter if one does abstract algebra or
       | linear algebra or combinatorics or number theory or 2D geometry
       | or whatnot at the beginning. Any foundational course in any
       | branch of mathematics, or any book on proofs, will fulfill this
       | need. People learn in different ways and have affinities for
       | different topics, so some subjects will be easier and/or more
       | interesting for them, so aspiring mathematicians should start
       | with a topic they're at least initially entertained by. If you
       | don't know where to start, one fun (for me) topic is the game of
       | Nim; other combinatorics topics are also elementary and
       | entertaining to think about. I'm fairly sure that if I had to
       | take this suggested curriculum as an undergraduate, I would have
       | picked a different major entirely, I personally find analysis
       | quite difficult :(
       | 
       | 2. One's first foray into a topic should be a one-semester
       | course, not a textbook. Lecture notes for many courses are freely
       | available online also, so you don't have to pirate the books you
       | want if you aren't willing to pay $100 :P The reason is this:
       | courses are curated by a mathematician to teach students the
       | basics of a topic in one semester, so they will better highlight
       | what you need to know, like important theorems, and have a more
       | careful selection of problems. If you're confused, you can read
       | the relevant textbook chapters. On the other hand textbooks are
       | more like comprehensive references - reading a textbook through
       | and doing all the problems will make you an expert at the
       | material, but it's not as time-efficient (or interesting) as a
       | course.
       | 
       | 3. There are benefits to diving very deeply into a topic, but IMO
       | one's mathematical experience is much richer if there's more
       | consideration for breadth, especially when you're starting out. A
       | student learning basic real analysis would benefit from
       | understanding some point-set topology (not just the metric
       | topology that usually begins these courses) and seeing how (some
       | of the) pathologies of topological spaces disappear when you
       | impose a metric and then you get things like being Hausdorff or
       | having many different definitions of compactness coincide. After
       | learning real and complex, of course one could move onto
       | differential equations, but there are so many other ways to
       | branch out, like exploring differential topology or learning
       | about measures & other forms of integration, which also meshes
       | very nicely with statistics. Exploring different branches
       | emphasizes that there are so many directions you can go with
       | math, even when you're just starting out, and gives you a better
       | feel about how "math" is done, as opposed to just the techniques
       | for a specific topic.
       | 
       | This is my first comment on HN, so please let me know how I can
       | improve this comment!
        
       | tzs wrote:
       | Overall a pretty decent list, although I would suggest
       | considering some tweaks.
       | 
       | For real analysis it recommends as essential Abbott's
       | "Understanding Analysis" and Rudin's "Principles of Mathematical
       | Analysis". If you "haven't gotten your fill of real analysis"
       | from those it recommends Spivak's "Calculus".
       | 
       | I'd consider promoting Spivak to essential, but using it for
       | calculus rather than real analysis, replacing their
       | recommendation of Stewart's "Calculus: Early Transcendentals".
       | 
       | By doing calculus with a more rigorous, proof-oriented
       | introductory calculus book like Spivak, there is a good chance
       | you won't need a separate introduction to proofs book so can drop
       | the recommended Vellemen's "How to Prove It: A Structured
       | Approach".
        
         | jeffreyrogers wrote:
         | I'll second this. "How to Prove It" gets recommended a lot, but
         | I couldn't get through it. I found it terribly boring and
         | unmotivated. Some people can power through dry material but I'm
         | not one of them. I found it much easier to learn to write
         | proofs when they were related to topics I was interested in.
        
         | l33t2328 wrote:
         | Spivak is a better analysis book than Abbot.
        
       | irrational wrote:
       | I never got beyond algebra/geometry in High school. I think I had
       | to take one 100 level math class in college, but it was basically
       | a review of HS math. Oh, and I had to take a stats class for non-
       | technical people in graduate school. That was my worst graduate
       | class by far. But, I would like to learn some more math, like
       | calculus. I'm hoping to get to it when I retire in a decade or
       | so.
        
       | foobarbecue wrote:
       | "... but make sure you get the paperback or hardcover version for
       | readability purposes."
       | 
       | As opposed to... the ebook?
        
       | musgravepeter wrote:
       | I've been on a Math journey since I retired a couple of years ago
       | and I agree with all the books mentioned that I know and look
       | forward to picking up some of the one I do not know. I agree baby
       | Rudin is essential, but I find it tough going.
       | 
       | Some books I liked for self study because they have answers:
       | 
       | Introduction to Analysis, Mattock.
       | 
       | Elementary Differential Geometry, Pressley.
       | 
       | There is also recently Needham's Visual Differential Geometry and
       | Forms, which is great.
       | 
       | Edit: I should also mention Topology without Tears (free, online,
       | very good) https://www.topologywithouttears.net/
        
         | selimthegrim wrote:
         | Surprised Arnol'd isn't mentioned for ODEs.
        
         | auggierose wrote:
         | Very pretty book (Needham's), will check it out! I think over
         | 20 years ago I actually attended a house party that Needham was
         | giving in SF. It's a small world.
        
         | voldacar wrote:
         | Those are good, I also really like Visual Complex Analysis
        
         | threatofrain wrote:
         | Consider Analysis 1/2 by Terence Tao for introduction to
         | analysis.
        
         | vermarish wrote:
         | I think learning Real Analysis from baby Rudin is like learning
         | Probability Theory from Wikipedia. It's so encyclopedic that if
         | it's your first look at real analysis, it will be too dense to
         | understand, but if it's your second or third look, you will
         | find beauty in its brevity.
        
         | susanrigetti wrote:
         | Agree that Baby Rudin is VERY difficult to study on its own. I
         | recommend only studying it alongside the other two books I
         | listed: Abbott's Understanding Analysis and Spivak's Calculus
         | (which has a solutions manual). Abbott in particular is very
         | straightforward (at least in comparison with baby Rudin haha)
        
           | tzs wrote:
           | Another point for Abbott is that it was one of the ~400 books
           | Springer made available for free download near the start of
           | the pandemic. I remember there were a few scripts here on HN
           | back then to grab all those books, so many here probably
           | already have a copy.
        
       | graycat wrote:
       | Calculus: I suggest just forget about "precalculus" and, instead,
       | just get a good calculus book and dig in.
       | 
       | There are two main parts of calculus, and both can be well
       | illustrated by driving a car. In the first part, we take the data
       | on the odometer and from that construct the data on the
       | speedometer. The speedometer values are called the (first)
       | _derivative_ of the odometer values. In the second part we take
       | the speedometer values and construct the odometer values. The
       | odometer values are the _integral_ of the speedometer values. In
       | notation, let t denote time measured in, say, seconds, and d(t)
       | the distance, odometer value, at time t. Let s(t) be the speed at
       | time t. Then in calculus
       | 
       | s(t) = d'(t) = d/dt d(t)
       | 
       | And d(t) is the integral of speed s(t) from time t = 0 to its
       | present time.
       | 
       | Those are the basics.
       | 
       | Applications are all over physics, engineering, and the STEM
       | fields.
       | 
       | Linear Algebra: The subject starts with a _system_ of
       | _simultaneous_ linear equation. The property _linearity_ is
       | fundamental, a pillar of math and its applications. The STEM
       | fields are awash in linearity. E.g., a concert hall performs a
       | linear operation on the sound of the orchestra. E.g., in
       | calculus, both differentiation and integration are linear. In the
       | STEM fields, when a system is not linear, often our first step is
       | to make an attack via a linear approximation. E.g., perpendicular
       | projection onto a plane is a linear operator and the main idea in
       | _regression analysis_ curve fitting in statistics.
       | 
       | Most of math can be given simple intuitive explanations such as
       | above.
        
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