Integral of Sin(theta)/Sin(theta/2)

by 3uc1id
Tags: integral
3uc1id is offline
Oct23-07, 03:56 AM
P: 7
The title says it all. im trying to integrate that but im not sure what substitution to use. i tried u=cos(theta/2) but something is not coming out right. does anyone have any suggestions? they would be well appriciated. thanks
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cristo is offline
Oct23-07, 04:38 AM
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P: 8,287
Can you write sin(theta) in terms of sin(theta/2)?
sutupidmath is offline
Oct23-07, 07:58 AM
P: 1,635
well, since thw OP hasn't shown up yet, i am going to make it a little bit easier for him.
Like cristo suggested you need to write sin(theta) in terms of sin(theta/2)
notice that sin(theta)=sin(2(theta/2)), now applying the double angle forumula for sin, what do we get?? like sin(x+y) = sin(x)cos(y)+cos(x)sin(y), now apply the same thing here, just notice that in our case we have x=y. Can you go from here??

3uc1id is offline
Oct24-07, 05:38 AM
P: 7

Integral of Sin(theta)/Sin(theta/2)

ok tnx. i finally got it but at the end i integrated from 0~pi. to get it.

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