>> help tf
tf - Transfer function model

    Use tf to create real-valued or complex-valued transfer function models, or to
    convert dynamic system models to transfer function form.

    sys = tf(numerator,denominator)
    sys = tf(numerator,denominator,ts)
    sys = tf(numerator,denominator,ltiSys)
    sys = tf(m)
    sys = tf(___,Name,Value)
    sys = tf(ltiSys)
    sys = tf(ltiSys,component)
    s = tf('s')
    z = tf('z',ts)

h=tf([1 4],[1 4 40])
pole(h)
zero(h)
figure
step(h)

h1=tf([10 40],[1 4 40])
pole(h1)
zero(h1)
figure
step(h1)

x = -2.9:0.2:2.9;
y = exp(-x.*x);
bar(x,y)

x = 0:0.25:10;
y = sin(x);
stairs(x, y)