A two-dimensional potential exists on a unit square area (0≤x≤1, 0≤y≤1) bounded by ``surfaces'' held at zero potential. Over the entire square there is a uniform charge density of unit strength (per unit length in z). Using the Green function of Problem 2.15, show that the solution can be written as
Φ(x,y)=π3ϵ04m=0∑∞(2m+1)3sin[(2m+1)πx]{1−cosh[(2m+1)π/2]cosh[(2m+1)π(y−21)]}