s domain to complex domain?

clc
clear all
A=[-0.0295 0.0478 0 -9.81;-0.1777 -1.4411 120 0;0.0005 -0.033 -1.5345 0;0 0 1 0]
B=[0;-12.81;-6.59;0]
C=[0 0 0 1]
D=[0]
[num ,dem]=ss2tf(A,B,C,D)
[z,p,k]=tf2zp(num,dem)
t=linspace(0,100,100)
sys=tf(num,dem)

i want this system in 's' domian to change into complex domain simply by subsituting 'jw' in place of 's' where 'w=0.1 rad/s'

then i want the magnitude of that complex domain can i do it in matlab

Answer 1

[Paul]

Some functions that may be of interest:

doc freqresp
doc abs