function [lam,x] = rqi(A,x,numsteps)
for j=1:numsteps
    lam=(x'*A*x)/(x'*x);
    y=(A-lam*eye(size(A)))\x;
    [m,r]=max(abs(y));
    x=y/y(r);
end
lam = (x'*A*x)/(x'*x);