[alfiedotwtf]

OP wants it from first principles as their maths is "poor" . I don't think Spivak is a good choice to jump right into calculus.

If OP wanted a more softer approach, Spivak's Hitchhiker's Guide to Calculus is probably a better option first before going full Spivak.

[WallWextra]

I honestly couldn't tell what he meant, whether he had stumbled through calc 3 and gotten sick of memorizing arbitrary rules, or if he can't solve a quadratic.

I tried to include some good high-school level math resources.