%%
close all;

set(0,'DefaultLineMarkerSize',12);
gain = -20;
zeros = [2,-5];


poles = [-4, -10 , 1+2j, 1-2j];
sys1 = zpk(zeros,poles,gain);%  Constructs zero-pole-gain mode

sys1=tf(sys1); % converts any dynamic system SYS to the transfer function representation

K = -[0,0.5,0.75,1,2];

%%
figure;
 
k = K(1);
sys = feedback(sys1, k); % returns a model object sys for the negative feedback interconnection of model objects sys1,k.
pzmap(sys); % creates a pole-zero plot of the continuous or discrete-time dynamic system model sys
hm = findobj(gca, 'type', 'line'); % returns the graphics root object 
set(hm, 'markersize', 12,'LineWidth',2)
hold on;
%%
k = K(2);
sys = feedback(sys1, k);
pzmap(sys);
hm = findobj(gca, 'type', 'line');
set(hm, 'markersize', 12,'LineWidth',2)
hold on;
%%
k = K(3);
sys = feedback(sys1, k);
pzmap(sys);
hm = findobj(gca, 'type', 'line');
set(hm, 'markersize', 12,'LineWidth',2)
hold on;
%%
k = K(4);
sys = feedback(sys1, k);
pzmap(sys);
hm = findobj(gca, 'type', 'line');
set(hm, 'markersize', 12,'LineWidth',2)
hold on;
%%
k = K(5);
sys = feedback(sys1, k);
pzmap(sys);
hm = findobj(gca, 'type', 'line');
set(hm, 'markersize', 12,'LineWidth',2)
hold on;

legend('0', '.5','.75','1','2')


%%  rlocus(-sys1) calculates and plots the root locus of the SISO model sys.
figure;
rlocus(-sys1)