No! Actually, you're doing well!
See my signature, that'll feed you up. (Integration by parts.)
This question is really confusing..I'm frustrated with it..
I tried solving it..
by these two steps:
∫cos^(n-1) x. cosx dx
∫cos^(n-1) x d(sinx)
I then stopped..I felt it's becomming more complicated..can ne1 help by giving me an easier way?