### Author Topic: Lec 23 Possion formula clarification  (Read 16589 times)

#### Kun Guo

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##### Lec 23 Possion formula clarification
« on: November 10, 2012, 05:33:03 PM »
Attached picture is a screen shot of online notes lecture 23. I was wondering if there is an addition r in front of sin(n*theta) in (12). Also, is there missing a^(-n) in calculating An and Cn?

#### Victor Ivrii

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##### Re: Lec 23 Possion formula clarification
« Reply #1 on: November 10, 2012, 05:43:06 PM »
Good catch

#### Miranda Jarvis

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##### Re: Lec 23 Possion formula clarification
« Reply #2 on: November 18, 2012, 03:14:20 PM »
I don't understand, if in equation (12) we are plugging in r=a to eq(10) how is there still and r involved as a variable?

#### Victor Ivrii

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##### Re: Lec 23 Possion formula clarification
« Reply #3 on: November 18, 2012, 03:26:52 PM »
I don't understand, if in equation (12) we are plugging in r=a to eq(10) how is there still and r involved as a variable?

We plug $r=a$ to recover coefficients (which do not depend on $r$). After they are recovered we plug them to the original expression for $u$ which  still contains $r$.

#### Aida Razi

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##### Re: Lec 23 Possion formula clarification
« Reply #4 on: December 08, 2012, 01:10:03 PM »
I was wondering if Cn has to be sin(nÎ¸) instead of cos(nÎ¸)?

#### Victor Ivrii

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##### Re: Lec 23 Possion formula clarification
« Reply #5 on: December 08, 2012, 02:49:18 PM »
I was wondering if Cn has to be sin(nÎ¸) instead of cos(nÎ¸)?

Yes, corrected.