How do I write the scrip for this problem? The one I wrote doesn't give me the same answer. Every tutorial I watched hasn't helped.

clear all
KK=1;clf
while (35>KK)&&(KK>0);
    G=tf(1,[1 4 9 0]);
    Gc=feedback(G,KK);
    t=[0:1:10]; 
    [y,t]=step(Gc,t);
    plot(t,y);
    hold on
    KK=KK + 5;
end

Answer 1

[goerk]

Td = A/s is already the step function.

figure;
for KK = [1 5:5:25]
    Gc=tf([1 0],[1 4 9 KK]);
    t=[0:0.1:10]; 
    [y,t]=step(Gc,t);
    plot(t,y);
    hold on
end

or you can replace step by impulse in your code.

[Ashkhen Aristakessian]

I appreciate your help Goerk.