n=5; alpha=2.2; A=zeros(n,n); for i=1:n-1 A(i,i)=2+alpha; A(i+1,i)=-1; A(i,i+1)=-1; end A(n,n)=2+alpha; [z,theta]=compito(n,alpha); b=zeros(n,1);b(1)=theta; x=[z;1]; A*x-b