MATLAB DOES NOT CALCULATE THE ABSOLUTE VALUE

I USE THE FUNCTION abs ON MATLAB, BUT WHEN I RUN THE PROGRAMM DOES NOT GIVE ME THE RIGHT RESULT WITH ROOTS

clear all

close all

clc

%ESERCITAZIONE DI CALCOLO_2

%PUNTO_1

syms s omega i

a=2;

b=2;

c=9;

d=5;

e=6;

f=2;

n=(b*s+1)*2*a;

x=(c+f)*s+1;

y=(d+e)*s+1;

z=(c+a)*s+1;

h=(d+f+1)*s+1;

G = (n)/(x*y*z*h)

disp('FUNZIONE DI TRAFERIMENTO IN FUNZIONE DI OMEGA ')

G_OMEGA=subs(G,s,i*omega)

AR_OMEGA=abs(G_OMEGA )

Answer 1

[Walter Roberson]

To get anywhere useful in a few lines, we have to make the unjustified assumption that the variable i corresponds to sqrt(-1)

syms Or Oi real
subs(subs(AR_OMEGA, [i, omega] , [1i, Or+1i*Oi] ), [Or, Oi], [real(omega), imag(omega)] )

ans =

(4*(4*real(omega)^2 + (8*imag(omega) - 4)^2/16)^(1/2))/((64*real(omega)^2 + (8*imag(omega) - 1)^2)^(1/2)*(121*real(omega)^2 + (11*imag(omega) - 1)^2)^(3/2))