- #1
sydfloyd
- 3
- 0
Homework Statement
This isn't really a homework question, but something I've been wanting to know out of curiosity in David Griffiths' Introduction to Electrodynamics.
On pages 131 and 132, there is a Fourier series,
[tex]V(x,y) = \frac{4V_0}{\pi}\sum_{n=1,3,5...}\frac{1}{n}e^{\frac{-n \pi x}{a}}\sin{\frac{n \pi y}{a}}[/tex]
The author then says that the series can be rewritten as
[tex]V(x,y) = \frac{2V_0}{\pi} \arctan{\frac{\sin{\frac{\pi y}{a}}}{\sinh{\frac{\pi x}{a}}}}[/tex]
The author says "the infinite series ... can be summed explicitly (try your hand at it, if you like) ..." so I got curious and decided to take a shot at it.
I have been trying to figure out how to get this result all day, but after a few sheets of paper, I am still lost... Any help would be much appreciated.
P.S. I have not taken a course on complex analysis.
Homework Equations
[tex]\sin{u} = \frac{e^{iu}-e^{-iu}}{2i}[/tex]
[tex]\sinh{u} = \frac{e^{u}-e^{-u}}{2}[/tex]
[tex]\arctan{u} = \frac{i}{2}\ln{\frac{1-iu}{1+iu}}[/tex]
[tex]\arctan{u} = \sum_{n=0}^{\inf} \frac{(-1)^n}{2n+1} u^{2n+1}[/tex]