# Boundary value problem: local stifness matrix

## Homework Statement

Given a BVP:

$$\Delta(u)+u=1$$ in $$\Omega$$
u=0 on $$\partial\Omega$$
using linear piecewise functions,
calculate the corresponding local stiffness matrix on the reference triangle :
{(x,y); 0<=x<=1, 0<=y<=1-x}.

The domain is a square with one point in the middle (at (0.5,0.5))

## The Attempt at a Solution

Does anyone know where i can start?