A=[4 -1 1 0 0;1 3 -1 0 0; 0 1 1 0 0; 0 0 0 2 1; 0 0 0 1 8];
[lambda,x,g] =Potenze(A,100,sqrt(eps));

plot(g)
hold on

yline(eigs(A,1,'largestabs'),'--k')

[lambda0,y,g] =PotenzeInverse(A,8.1,100,sqrt(eps))

[P,H]=hess(A);