E=200e6;
A=0.04;
Lb=5;
P=10;
q=2;
L=Lb/2;
k1=E/L*A*[1 -1; -1 1];
k2=E/L*A*[1 -1; -1 1];
f1=[q*L/2; q*L/2];
f2=[q*L/2; q*L/2];
K=zeros(3,3);
F=zeros(3,1);
K(1:2,1:2)= K(1:2,1:2) + k1;
K(2:3,2:3)= K(2:3,2:3) + k2;
F(1:2)= F(1:2)+ f1;
F(2:3)= F(2:3)+ f2;
F(3)= F(3) + P;
K(1,:)= [];
K(:,1)= [];
F(1)= [];
u=K\F