- #1
treynolds147
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Homework Statement
A potential satisfies ##\nabla^{2}\Phi=0## in the 2d slab ##-\infty<x<\infty##, ##-b<y<b##, with boundary conditions ##\Phi(x,b)=V_{s}(x)## on the top and ##\Phi(x,-b)=-V_{s}(x)## on the bottom, where ##V_{s}(x)=-V_{0}## for ##-a<x<0##, and ##V_{s}(x)=V_{0}## for ##0<x<a##, and repeats periodically outside this window.
Homework Equations
The Attempt at a Solution
So this is clearly a separation of variables problem, and I'm splitting into two parts - one which treats the bottom boundary condition, and one which treats the top boundary condition (while the opposite condition is set to zero). However, I feel really unsure of what I'm doing. So far I have the potential in relation to the bottom BC as ##\Phi=\sum_{n}A_{n}\sin\frac{n\pi x}{a}\sinh\left(\frac{n\pi y}{a}\right)##. I make no claim that this is entirely right. I suppose I'm not entirely sure how to set up the general function in the first place, or how to evaluate the coefficients while taking into account the periodic nature of the BC. Any nudges to get me started on the right foot?