1. The problem statement, all variables and given/known data Integrate Cosx/1+sinx dx from 0 to pi/2. "The question does not assume knowledge of integration by parts." 2. Relevant equations 3. The attempt at a solution Could it be found using the quotient rule? If not, is there any way of proving it without using integration by parts? Mod note: Edited this post by moving text, to comply with our rules about including an attempt.