# Thread: integration problem..plz help, I'm clueless...

1. ## integration problem..plz help, I'm clueless...

This question is really confusing..I'm frustrated with it..
evaluate:

∫cos^(n)x

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?

2. No! Actually, you're doing well!

See my signature, that'll feed you up. (Integration by parts.)

3. Originally Posted by KAS
This question is really confusing..I'm frustrated with it..
evaluate:

∫cos^(n)x

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?
Note that this will never give you a definite answer, but what is known as a reduction formula. Look it up on Wikipedia.

4. Krizallid..thanx.. ur method seems to be very effective..ill try use it ..
mathstud yeh.. it doesn't seem to be the type of question where a definite answer will be found..ill try look at what u sed on wiki.it might be useful..

thanx again ...