function Lambda=Evaluate_Transformation_Matrix(Length,iEnd,Nodes)

node_j=iEnd(1);
node_k=iEnd(2);

x_j=Nodes{node_j}.x;
x_k=Nodes{node_k}.x;

y_j=Nodes{node_j}.y;
y_k=Nodes{node_k}.y;

Dx=x_k-x_j;
Dy=y_k-y_j;

cosf=Dx/Length;
sinf=Dy/Length;

Lambda=[ cosf sinf  0   0;
                 -sinf cosf 0   0;
                   0    0     cosf sinf;
                   0    0   -sinf cosf];


end