$\displaystyle \int3\theta\cos\thetad\theta = [3\theta][\sin\theta] - \int[\sin\theta][3]$

$\displaystyle u = 3\theta$

$\displaystyle dv = \cos\theta d\theta$

$\displaystyle v = \sin\theta$

$\displaystyle du = 3$

$\displaystyle 3\sin^{2}\theta - \int3\sin\theta$

$\displaystyle 3\sin^{2}\theta + 3\cos\theta + C$ - ?? Online homework says this is wrong.

$\displaystyle 3(\sin^{2}\theta + \cos \theta) + C$ - ?? Online homework says this is also wrong.