## Zarby Group Title Integral using parts of t^(2) sin(t) I got it to -t^2cos(t) dt+2Integral tcos(t) dt How and why do I have to use parts again to solve this? Thanks one year ago one year ago

1. KingGeorge

So you've gotten to the point $\int t^2\sin(t) dt=-t^2\cos(t)+2\int t\cos(t) dt$To finish solving this, you need to integrate $\int t\cos(t) dt$ using parts in the same way that you did the first integral.

2. KingGeorge

You have to use parts to solve it, because it's the best way of solving it after guessing.

3. Zarby

Why only integrate that side?

4. KingGeorge

What exactly do you mean?