I remember being scared of calculus. Now, look what I can do! (Although this is only differential calculus...)
I'm not bothered to post more of the formulae, but... I did write notes about all of this on a digital garden I'm working on. It's the second edition of my old digital garden, and it's called "toPi 2e". Check it out here!
I think it's interesting that you can find the gradient of things that aren't just linear functions. I heard that differentiation is good for things like water waves... or something.
Anyway, not much to say. Math is cool (when it's not confusing)!