1. The problem statement, all variables and given/known data I've come across integrals of exponential and trig functions and I have no idea how to do them. Integration by parts doesn't really work because they just derive into either e or another trig function. One of them is [itex]\int[/itex]sin(a)*sin(b - a)da Another is [itex]\int[/itex]e(a)*sin(a)da 2. Relevant equations sin(x + y) =sinx(cosy) + siny(cosx) cos(x + y) = cosx(cosy) - sinx(siny) sin^2(x) = (1 - cos2x)/2 3. The attempt at a solution I've tried to use the trig identity for sin(b-a), but that just gives an extremely long sin and cos statement that doesn't help. the one with e is even more confusing. How am I supposed to manually solve them?