1. The problem statement, all variables and given/known data Show that (forgive me for not knowing how to use latex) from x=0 to x=1 of: ∫cos([(2n+1)(pi)/2]x)*cos([(2m+1)(pi)/2)]x) dx = 0, for m ≠ n 2. Relevant equations The question tells me to use integral tables. 3. The attempt at a solution Using integral tables, I got ∫(1/2) [cos((A-B)x) + cos((A+B)x)] dx from 0 to 1. A, B are equal to (2n+1)pi/2 and (2m+1)pi/2 respectively. However, when I evaluate the integral and I get sines, the x merely becomes a 1 and I get a little confused after that. Any help would be greatly appreciated.