%  Figure 5.45  Feedback Control of Dynamic Systems, 8e 
%                   Franklin, Powell, Emami

clf
s=tf('s');
sysL1 = s/(s^2+s+4);  % from Eq. (5.86), with KA = 4
rlocus(sysL1);    % roots vs. K_T
axis([-5 2 -3 3])
hold on
 
KT=1;
R1=rlocus(sysL1,KT);  % plot roots with KT = 1
plot(R1,'s', 'MarkerSize', 10, 'MarkerFaceColor','k')
%plot(R1,'*')

title('Root Locus vs. K_T (K_T=1)')
%grid on
%hold off


set(gco,'LineWidth',4)