Use integration by parts to solve the following integrals:
(I don't know how to do an integral sign on this lol)
[integral] x^2 sin(3x) dx.
Now, I've solved it out and come to the conclusion:
[-x^2/3 cos(3x)] + [2x/9 sin(3x) + C]
However the answer I have been given is
[(2/27 - x^2/3) cos(3x)] + [2x/9 sin(3x) + C]
Similar but not quite right. Could anyone please tell me where I'm going wrong