close all;
clear all;
sys=tf([1],[1 3 3 -7])
rlocus(sys);
N=6;
for t=1:N
   [a,b]=rlocfind(sys);
   system=feedback(sys,a)
   H(t)=system;
end
figure(N)
for t=1:N
    subplot(3,2,t)
    step(system);
end