% Fig. 5.43   Feedback Control of Dynamic Systems, 8e 
%             Franklin, Powell, Emami


clf 
s=tf('s');
sysL = -(s-6)/(s*(s^2+4*s+13));
rlocus(sysL)
hold on
axis([-6 10 -6 6])
title('Negative locus of (s-6)/s(s^2+4s+13)')
z=0.1:.2:.9;
 wn= 1:6;
 sgrid(z, wn)
 hold off

 set(gco,'LineWidth',4)