The Neumann problem for a rectangle

Submitted by vic777 on Sat, 11/24/2007 - 04:19.

What is the solution for this equation?

$\nabla^2u=0, 0<x<\pi,0<y<\pi,<br /> u_x(0,y)=0,<br /> u_x(\pi,y)=0,<br /> u_y(x,0)=sinx,<br /> u_y(x,\pi)=cosy$