1. ## integrating trigs

hi guys

i just recently joined this forum in hope that some of you may help me with my maths problems?

i'm having trouble integrating this problem:

I(n) = sin^n(x)dx in terms of I(n-2)

ps. i didn't put the integral sign at the front

i've tried for countless hours =\ hope someone can help. thank you

2. Originally Posted by eep
hi guys

i just recently joined this forum in hope that some of you may help me with my maths problems?

i'm having trouble integrating this problem:

I(n) = sin^n(x)dx in terms of I(n-2)

ps. i didn't put the integral sign at the front

i've tried for countless hours =\ hope someone can help. thank you
I dont understand yoru notation? you have $I(n)=\int{sin^{n}(x)dx}$ is that right?

3. Originally Posted by Mathstud28
I dont understand yoru notation? you have $I(n)=\int{sin^{n}(x)dx}$ is that right?

yea, that's right .. i didn't know how to type it up =\

4. Originally Posted by eep
yea, that's right .. i didn't know how to type it up =\
In that case..use integration by parts to get it into the desired form..let $u=sin^{n}(x)$

5. Originally Posted by Mathstud28
In that case..use integration by parts to get it into the desired form..let $u=sin^{n}(x)$
oo ic ic, thanks a bunch

6. Originally Posted by eep
hi guys

i just recently joined this forum in hope that some of you may help me with my maths problems?

i'm having trouble integrating this problem:

I(n) = sin^n(x)dx in terms of I(n-2)

ps. i didn't put the integral sign at the front

i've tried for countless hours =\ hope someone can help. thank you
this is just asking you for the reduction formula for sine. they derive this all over the internet. just write it as $\int \sin x \sin^{n - 1}x~dx$ and use integration by parts. let $u = \sin^{n - 1}x$ and $dv = \sin x$