% pkg load control
% t = 0:0.1:1000;
s = tf('s');
H = (s^2 + 5*s + 6) / (s * (s+1) * (s^2 + 10*s + 50));
pzmap(H);
% pkg load symbolic
% syms s t
% y = e^(-t) * cos(10*t) * heaviside(t);
% la