1. The problem statement, all variables and given/known data 1. Evaluate: [tex]\oint cos^2(x)dx[/tex] Using two different methods 2. Relevant equations 3. The attempt at a solution I have done it making the substitution of cos^2(x) = (1 + cos(2x))/2 but don't see how you can do this another way. Integration by parts doesn't seem to work and nor does substitution as far as I'm aware. Any ideas?