Discrete Poisson equation: Difference between revisions
→On a twodimensional rectangular grid
(→On a twodimensional rectangular grid: In the fourth row, changed some vdots to ddots. I think they make more sense here.) 

1 & ~4 & 1 & ~0 & ~0 & \ldots & ~0 \\
~0 & 1 & ~4 & 1 & ~0 & \ldots & ~0 \\
\vdots & \
~0 & \ldots & ~0 & 1 & ~4 & 1 & ~0 \\
~0 & \ldots & \ldots & ~0 & 1 & ~4 & 1 \\
