AbdelRahmanShady
Junior Member
- Joined
- Jul 20, 2021
- Messages
- 123
Kind of stupid question, but I am self learning calculus and is trying to prove rules along way like chain rule and power rule. My question is that I found that I cant substitute some dxs in equation with zero and leave others or I get wrong answer. But if do the substitution at one go, answer is right. so am I right or there are cases where even my second method fails. One more thing I sometimes use f(x)dx in other function as limit to zero as f(x)dx will approach zero with time. I used this fact mainly when proving composition rule but is this method correct or I just lucked out.