If this is where you're at, make sure you check out the famous Gilbert Strang's "Highlights of Calculus" series from MIT's OCW. He really boiled it down in those. [1]

1. https://www.youtube.com/playlist?list=PLFW_V3qDH5jRyfpD9uiq6...

If you like this kind of thing, I thought the 3Blue1Brown discussion on calculus was pretty good:

https://www.youtube.com/playlist?list=PLZHQObOWTQDMsr9K-rj53...

Apparently, the author (Paul Lutus) wrote the original Apple Writer [0] and "designed spacecraft components for the NASA Space Shuttle.[1]"

Neat!

0. https://en.wikipedia.org/wiki/Apple_Writer

1. https://arachnoid.com/administration/index.html

The author's 36pp PDF article (which he links to) has much more on the topic.

https://arachnoid.com/calculus/