First off, thanks for your help. I feel like a dope because everything I'm doing looks correct to me, but my answer is not the same as the book or solution manual gives! I'm usually so good at finding my mistakes. Thanks for taking the time to help. 1. The problem statement, all variables and given/known data http://img232.imageshack.us/img232/391/problemns1.jpg [Broken] 2. Relevant equations Where did I go wrong?? 3. The attempt at a solution http://img57.imageshack.us/img57/1832/solutionkn2.jpg [Broken] The book's answer is -1/4 (cos x)^4 + C even when I try to convert sines to cosines, I'm not getting that those two answers were the same.