- #1
Firepanda
- 430
- 0
http://img243.imageshack.us/img243/1816/laplaceds2.jpg
Right I have a fair few questions on this, it's relating to question 7 only, although you need to refer back to the equation derived from question 6.
1) I used the equation from q6. as a Fourier series substituting r=a. I end up with an An of:
An = (Vo * a^n * Pn)/pi
For n = odd (i.e 2n+1)
And An = 0 for n = even.
Now looking at the result I should get (at the end of q7.) my a^n should in fact be a^-n, it stays as a constant during my integration so I can't change it there, so where do I change it?
2) My Fourier series was on the interal from 0 to pi/2, now from my definition of a Fourier series the integral should go from -L to L with 1/L constant before the integration. What is my 1/L here? I used 1/pi, not sure if this is correct.
3) For the second Fourier series in the integral of pi/2 to pi, I used 1/pi again for my 1/L (as defined before) but my An here doesn't get as far as being able to integrate it as I get 0 before I start, so I assume I leave this part out of the whole question?
Basically from my first integration I get close but I have no constants to my polynomials as I'm supposed to, which makes me think my question at 3) shouldn't be 0...
I see the orthoganality help at the bottom, how do I use this here?
ANY help is much appreciated!
Thankyou
Right I have a fair few questions on this, it's relating to question 7 only, although you need to refer back to the equation derived from question 6.
1) I used the equation from q6. as a Fourier series substituting r=a. I end up with an An of:
An = (Vo * a^n * Pn)/pi
For n = odd (i.e 2n+1)
And An = 0 for n = even.
Now looking at the result I should get (at the end of q7.) my a^n should in fact be a^-n, it stays as a constant during my integration so I can't change it there, so where do I change it?
2) My Fourier series was on the interal from 0 to pi/2, now from my definition of a Fourier series the integral should go from -L to L with 1/L constant before the integration. What is my 1/L here? I used 1/pi, not sure if this is correct.
3) For the second Fourier series in the integral of pi/2 to pi, I used 1/pi again for my 1/L (as defined before) but my An here doesn't get as far as being able to integrate it as I get 0 before I start, so I assume I leave this part out of the whole question?
Basically from my first integration I get close but I have no constants to my polynomials as I'm supposed to, which makes me think my question at 3) shouldn't be 0...
I see the orthoganality help at the bottom, how do I use this here?
ANY help is much appreciated!
Thankyou
Last edited by a moderator: