Introduction to Calculus (2016)

Ha! Fast forward 6 year after undergrad and thats me.

I'm doing the Khan academy series on calculus, starting with single variable calculus to refresh my math, to relearn the math for ML and Data Science. It's not my day job but I'm interested in the space so I can understand things under the hood instead of just using libraries.

In college, I was more obsessed with getting an A in my classes, terrified of any lessor score, and all that at the cost of not understanding much at all but just repeating formulas and techniques on tests.

For my kids some day, the biggest lesson I can teach them is that it's okay to fail. Getting straight As doesn't matter much at all, and you should always question things and think critically.

On the other hand, a lot of things (not just in math) we think we understand are, in fact, simply memorized. And, by the way, that is not a bad thing - it is better to learn the multiplication table, for example, than to fail to "understand" it and give up. You can work on true understanding later; my advice, therefore, is to read as much as possible on a topic, however incomprehensible it may seem at first, just to get used to it and to make it look familiar, and do some exercises. You will soon feel that you understand something (even though you don't). That's the way we humans learn.

In a PDF on Project Gutenberg: Calculus Made Easy by Silvanus P. Thompson

http://www.gutenberg.org/ebooks/33283

Seconded. I did calculus decades before I became aware of this book, but in reading it now I think it's excellent, and very much wish I'd known it before.

By contrast, I didn't find the submitted book very engaging, but I'm sure it's a matter of taste, and others will disagree.

This book is amazing. But I'd suggest everybody to read the version edited by Martin Gardner in 1998[1]. The first version written by Thompson ignored the use of limit, and it also used terms that aren't used anymore. For example, the older book used the term 'differential coefficient' which is now known as derivatives[2].

[1] https://www.amazon.com/Calculus-Made-Easy-Silvanus-Thompson/...

[2] More about the difference between old and the new book https://en.wikipedia.org/wiki/Calculus_Made_Easy

Seems to assume an understanding of precalculus or advanced algebra 2

I'm in highschool in Canada and can confirm that we have covered both of those symbols.

I graduated Ontario high school in the last decade and grade 12 calculus (required for many university programs) covers both.

There is a footnote on page 10 that briefly explains both of those symbols, although I doubt many people would immediately understand the footnote if they weren't already familiar with the symbols and concepts.

The author explains his reasoning for PDF for this document here: https://arachnoid.com/latex/why_latex_pdf.html.

The author also has a Hacker News profile: https://news.ycombinator.com/user?id=lutusp