#232 overall
Calculus (Gilbert Strang)
MIT OpenCourseWare
2 recommenders · 2 threads · recommended in 2 years, 2013–2024 · score 1.8
MIT OpenCourseWare's video lecture series on single-variable calculus by Gilbert Strang, covering the big ideas of calculus with less emphasis on computation. Commenters point to the lectures as a free video resource.
Commenters describe Strang's lectures as a great series on the big ideas of calculus, and one calls them great video lectures on calculus and linear algebra.
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20062026
Gilbert Strang made a great series of lectures on the big ideas of calculus sans most of the computation - http://www.youtube.com/playlist?list=PLBE9407EA64E2C318
A lot of it depends on what exactly you want to do (in|with) tech. Plenty of developers get by with high-school algebra. At the more extreme end, if you want to write software for weather forecasting or other fields using numerical computation, simulation, etc., then you probably need a background roughly equivalent to a degree in maths. And there's a lot of "in between" those extremes.
For my money though, I'd say a good starting point would be:
1. Calculus through Calc III (as the Calculus sequence is typically structured in American universities)
2. Linear Algebra
3. Differential Equations
4. Probability Theory
5. Statistics
Sidebar: if you specifically want to work with cryptography / cryptanalysis, you probably want to study number theory, abstract algebra, and probably a bunch of other stuff that I don't know anything about. :-)
Resources? Hmm... there's a whole world of stuff out there, and plenty of previous HN threads discussing various books, blogs, courses, videos, etc. But you could do worse than using Khan Academy, and the ProfessorLeonard channel on Youtube. Other good Youtube channels include Michael Penn, 3blue1brown, blackpenredpen, Organic Chemistry Tutor, MathMajor (which is still Michael Penn - he has two channels), NancyPi, and MIT's OCW stuff (Gilbert Strang in particular has great video lectures on Calculus and Linear Algebra).
Also note that if you're self-studying (as opposed to taking a class at university) then it mostly doesn't matter what edition of books you use. And you can find used copies of older editions of maths books for pretty much every topic imaginable for pretty cheap. Search on Alibris and then sort by "Price - Low to High" and you'll usually be able to find a book on your topic for $2.00 - $5.00 or so. If you prefer ebooks there are legitimately available free books on most subjects again, and there's always the pirate e-book sites if you want to go that route.