Boundary value problem: local stifness matrix

[sara_87]

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))

Homework Equations

The Attempt at a Solution

Does anyone know where i can start?

 

[NSAC]

which numerical method are you using?

 

[sara_87]

I am using the finite element method.
I forgot to mention, i fixed my problem, i know how to do this question :)