Need to get matlab to display the continuous time transfer function

clc;

% (b)

% state variable model
A = [1 3 0; -3 0 7; -5 -4 -8];
B = [-1; 0; 1];
C = [1 0 0];
D = 0;

% get numerator & denominator of transfer function using ss2tf
[num, den] = ss2tf(A,B,C,D);

% converting numerator & denominator to transfer function
system = tf(num,den)

system =
 
       -s^2 - 8 s - 7
  ------------------------
  s^3 + 7 s^2 + 29 s + 149
 
Continuous-time transfer function.

That is my code. Everything works [as] I get the right numerator and denominator.

The problem is the comman window won't display the transfer function and yes, I have the [Control System Toolbox] installed.

Answer 1

[Les Beckham]

Please explain exactly what the problem is. You need the Control System toolbox, not the "command tool box", whatever that is.

A = [1 3 0; -3 0 7; -5 -4 -8];
B = [-1; 0; 1];
C = [1 0 0];
D = 0;
%get numerator & denominator of transfer function using ss2tf
[num, den] = ss2tf(A,B,C,D);
%converting numerator & denominator to transfer function
system = tf(num,den);
display(system)

system =
 
       -s^2 - 8 s - 7
  ------------------------
  s^3 + 7 s^2 + 29 s + 149
 
Continuous-time transfer function.

which display(system)

/MATLAB/toolbox/control/ctrlmodels/@tf/display.m  % tf method

[Michael]

that worked I overlooked such a simple thing thank you very much

[Les Beckham]

You are quite welcome. Please Accept the answer if it helped you.