% Problem 4.24
% 4.24(a)
num1=5;
den1=[1 2 0];
w=logspace(-1.5,2);
nyquist(num1,den1,w)
axis([-1.5 0 -40 40])
grid

% 4.24(b)
num2=10;
den2=conv([1 5 0],[1 10]);
figure(2)
nyquist(num2,den2,w)
axis([-0.08 0 -2 2])
grid

% 4.24(c)
num3=3;
den3=conv([1 1],[1 2]);
figure(3)
w=logspace(-2,2)
nyquist(num3,den3,w)
axis([-0.5 2 -1 1])
grid

% 4.24(d)
num4=[1 0 1];
den4=[1 1 0]
figure(4)
w=logspace(-1,2)
nyquist(num4,den4,w)
axis([-1.1 1.1 -6 6])
grid
