Hi everyone! Well we are asked to do $\displaystyle \int_{}^{} sin(3x)cos(5x)dx$ exculsively by integration by parts. Doing it by trig identities is pretty easy, but once I do this one by integration by parts, including the integrand $\displaystyle \int_{}^{}vdu$, I always end up getting $\displaystyle 0=0$. Thanks you guys in advance!