helterskelter 1 day ago

I've been relearning trigonometry lately by myself for navigation and astronomy; not for work, just curiosity I guess. One book I've really enjoyed is Heavenly Mathematics by Van Bremmelen. It's a spherical trig textbook, but it's written by a math historian who describes how trigonometry was gradually developed over human history and he discusses its early proofs, methods and applications. I have to confess that the historical approach has really helped me develop a more complete mental picture and appreciation of the math itself. Understanding the "how" and "why" of its development, and seeing the early practical need and implementation for some of this stuff has made the topic a lot more engaging.

  • shanusmagnus 1 day ago

    It seems like you'd get a lot deeper understanding by doing it that way, and be much more able to adapt the knowledge to the real world, vs only knowing how to solve problems in the exact form they were presented to you. I had so many semesters of undergrad math, did fine, but feel like I took basically nothing from it.

  • srean 1 day ago

    This is a very entertaining hobby to have. Wishing you a lot of fun.

    Next stop, making sundials and reading astrolabe.

    I was so surprised to know that Chaucer had such interest in the workings of an Astrolabe. It's not much of a surprise if you think that Astrolabe were the pocket GPS, pocket watch, pocket star chart of those times.

    • helterskelter 23 hours ago

      Honestly I've been thinking about putting some standing stones in my yard to act as solar clock and calendar, maybe doing a lunar calendar as well...

      I don't that's against code (yet).

      • srean 23 hours ago

        All the best for your Stonehenge.

        Just knowing that the Sun doesn't really rise on the East (barring exceptions) is a fun reward in itself.

        Solarigraphy and Analemma tracking are great fun if you have the luxury of an undisturbed access to the skies.

        https://en.wikipedia.org/wiki/Solarigraphy

  • helterskelter 1 day ago

    Sorry, author's name was Van Brummelen, not Van Bremmelen.

    • srean 1 day ago

      You know you can edit your comment right. You are still in that edit window.

  • throwaway81523 10 hours ago

    Is spherical trig still a thing? Calculation is so cheap now. If you want to find the spherical distance between cities from first principles, it's easiest to convert to 3D rectangular coordinates and find the angle ABC from the vector dot product, where A and C are the cities and B is the center of the earth. Same for other types of navigational calculations like headings. But, I've never looked into it really.

    • helterskelter 30 minutes ago

      Yep, it's mostly used in for navigation, especially as a backup in case GPS fails (in the case of a lightning strike on a sailboat, for instance, probably all your electronics are toast). The military still uses it with slide rules/log tables, in case of jamming, etc. It kind of "disappeared" sometime after WWII, and there aren't many new books on it, but you'll see it come up in computer graphics and animation quite a bit, and I'm pretty sure it's used extensively in surveying still.

  • soulofmischief 4 hours ago

    This is the approach I take to learning just about everything: Ask the five W's: Who, what, when, where, why?

    It compounds, as you learn more history, you're able to connect more and more dots, and learning new information becomes easier on average.

ykonstant 4 days ago

This is one of the best generalist books on mathematics ever published. I highly recommend it.

hamburgererror 11 hours ago

I'm looking for mathematics books that take the time to explain with words and sentences what is actually going on when they introduce a new theorem, something that focuses on meaning.

Anyone knows if such books exist?

  • rramadass 10 hours ago

    Not sure what you are looking for. Mathematics is just a shorthand, precise language to represent wordy natural language concepts succinctly. So when you see the symbols you have to expand it in your mind (and/or use paper/pencil) into equivalent natural language concepts which the symbols model. There are no shortcuts but only time, effort and patience.

    There are a bunch of books on how to do/understand Proofs/Theorems etc. but without knowing what you are specifically looking for i can only make some general recommendations;

    1) How to Read Proofs: The ‘Self-Explanation’ Strategy (pdf) - http://www.ma.rhul.ac.uk/~uvah099/Maths/HoddsAlcockInglisSel...

    2) How to Read, Understand and Study Proofs - https://mikepawliuk.ca/2014/03/31/how-to-read-understand-and...

    3) How to Think Like a Mathematician by Kevin Houston - https://en.wikipedia.org/wiki/How_to_Think_Like_a_Mathematic...

    • hamburgererror 9 hours ago

      Thanks for the references, I'll have a look. I can tell you what I don't want: books that throw theorems one after the other without any context, like Baby Rudin [1] for instance.

      I tried once to read Terence Tao's Analysis I [2], it's really good but my main problem was that I wasn't able to know if my proofs are correct when I do an exercise. So maybe the solution is to get a teacher.

      [1]: https://en.wikipedia.org/wiki/Principles_of_Mathematical_Ana...

      [2]: https://terrytao.wordpress.com/books/analysis-i/

      • rramadass 8 hours ago

        AI is a godsend here. One can use the Socratic (aka Maieutic) method with AI to both explain and verify one's understanding. For some references see https://news.ycombinator.com/item?id=48342887

        I have used Google's "AI Overview" and "AI Mode" profitably to have it explain new concepts to me in simple terms and also have had it verify my own understanding of something. The reason i prefer it is because it is a search-driven reasoning engine and thus gives references (in tooltips) directly to the latest sources/articles on the web from which it synthesized its answers.

      • BeetleB 2 hours ago

        I'll second the suggestion to use a good LLM.

        I haven't tried it with analysis, but I did for linear algebra. It would quickly spot flaws in my proof.

    • dtj1123 1 hour ago

      Kevin Houston introduced me to the concept of a number system. Cool guy.

      Hard disagree that mathematics is just a shorthand notation though. It's a body of thought, independent of the symbols you choose to represent it.

  • dtj1123 1 hour ago

    I recently started Introduction to Probability theory by Blitzstein and it feels a lot like what you're referring to.

    The author introduces something called 'proof by story', where instead of just running through algebra to prove equivalence of two expressions, you describe a single physical scenario in two ways that each intuitively correspond to the two expressions. I've never seen maths done this way before, but I have to say it works brilliantly.

throwaway81523 10 hours ago

This is a great series. I was awed by it in high school. Some parts were too advanced for me (and probably still are), but I got a lot out of other parts.

__rito__ 1 day ago

This is a great book if you already know good amount of Math. It helps you fit things into a bigger picture. Really appreciate the fact that something like this exists.

  • mmooss 23 hours ago

    FWIW the Preface says it's written for people with secondary school mathematics education - whatever that meant in the Soviet Union in the 1950s.

    • kmt-lnh 23 hours ago

      Yeah, but they meant Soviet secondary school...

    • elzbardico 22 hours ago

      Soviet primary and secondary education on math was one of the few good things of the regime.

      Culturally, mastery of mathematics, engineering, chess and technical inteligence were a source of social status and prestige.

      Yes, an engineer could have been badly paid, he was not free in a liberal sense, be subject to the vagaries of political paranoia waves, but he commanded a certain level of social respect that even good paid engineers in the sillicon valley can hardly imagine. A soviet physicist could be underpaid and constrained by bureaucracy, but being introduced by your parents as a professor of the Keldysh Institute of Applied Mathematics or the Steklov Mathematical Institute in your home town give you almost an aura. Kids would look at you and dream of being admitted to secondary institutions like Kolmogorov's boarding school at the Moscow State University.

      Given that, it was as likely for people in political positions of power to have a good mathematical background as it is to find a lawyer in the US Capitol.

      • rramadass 15 hours ago

        > Culturally, mastery of mathematics, engineering, chess and technical intelligence were a source of social status and prestige.

        This is what has severely degraded in current-day global society/culture and due to globalization exported everywhere.

        However, Soviet-era Science/Mathematics books are still highly regarded/prized in many countries by the older generation.

    • rramadass 15 hours ago

      Right. The book is accessible to a smart student in grades 9-10 and most everybody in grades 11-12.

rohityin 1 day ago

The only mathematics books I ever read was textbooks in school but now as adult I want to start from scratch.

nathan_compton 22 hours ago

This book is really fascinating because it contains a surprising amount of Soviet ideology. The authors repeatedly state that mathematics is posterior to the material world, not prior to it. That is, mathematics is just the observation of regularity in the world, particularly those discovered by people working to create things. Contrast this with the still heavily idealistic world of western mathematics, where mathematicians are more likely to sympathize with the notion that numbers are real things somewhere out there whose structures the real world supervenes upon in some way.

Interesting stuff!

Even though I favor the Soviet view of mathematics personally (I do not think numbers "exist" out there independent of the material world), I think this approach hampers the didactic goals of the text and probably hurt Soviet mathematics as well. The examples in the text are all highly concrete (literally things like rubber mats when discussing curvature). This very down to earth style makes the abstract notions of curvature in other contexts (for example, general relativity) more difficult to grasp, in my opinion.

On the other hand, some people prefer strong, material, examples of mathematical ideas. This book definitely provides that. The section on affine maps in terms of fixing the plane of a surveillance airplane photograph is beautifully concrete.

mohamez 23 hours ago

Where can I find mathematical book titles like this one?