Evalutate

.

I started by letting

and ?

I believe I need to use polar coordinates, but I not sure how. Any help would be greatly appreciated.

Thank you

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- Apr 14th 2010, 12:26 PMDanneedshelpDifficult integral
Evalutate

.

I started by letting

and ?

I believe I need to use polar coordinates, but I not sure how. Any help would be greatly appreciated.

Thank you - Apr 14th 2010, 02:02 PMzzzoak
Please use this

.

Notice that

.

Lets find integral

- Apr 14th 2010, 03:58 PMDanneedshelp
- Apr 14th 2010, 04:19 PMzzzoak

and

- Apr 14th 2010, 06:13 PMSudharaka
- Apr 14th 2010, 08:55 PMDanneedshelp
- Apr 14th 2010, 09:29 PMDanneedshelp
. Let and , then

.

Thus,

.

The correct answer is . So, I am still stuck on this problem. I am not sure what I am doing wrong. I would have the correct answer if I integrated from 0 to with respect to , but I don't thank that would be proper.

Note: The polar coordinates make things a little confusing, because the in the integrand is a constant and not related to . - Apr 14th 2010, 11:18 PMHallsofIvy
You asserted, originally, that the problem was to integrate

I suspect you have accidently switched to finding

and so your answer needs to be divided by 2. - Apr 15th 2010, 09:45 AMDanneedshelp
I'm sorry to keep bringing this up, but I dont see how

http://www.mathhelpforum.com/math-he...2ecbd45d-1.gif

and the rest of the expression above. I don't really understand your notation. I do see how you are using integration by parts, but I don't understand . I just don't see the equality posted above.

Sorry for beating a dead horse, but I want to understand this.

Thank you again. - Apr 15th 2010, 11:03 AMDeadstar
- Apr 15th 2010, 11:33 AMDeadstar