“Too Much Calculus” by Gilbert Strang, who taught me linear algebra in the late Victorian era and is still at it. Linear algebra is what we use for everything in the real world. Calculus is elegant, but you’ll never actually have to solve an integral. http://www-math.mit.edu/~gs/papers/essay.pdf …
Right! It’s super important to understand the fundamental concepts, I think. Formulas for derivatives and integrals of obscure trig functions, not so.