clear;
close all;
s=tf('s');
G=1/(s+2)

k=[0,1,2,3,10,50];

figure;
hold on;
t=0:0.01:2;

for i=1:6;
   G1=k(i)*G/(1+k(i)*G);
   step(G1,t);
end

figure;
rlocus(G);