Octave integration does not evaluate definite integral with symbolic variables - matlab

Question

I am trying to evaluate a convolution integral using the symbolic int() function and instead of returning a useful answer, my program is returning the integral itself. Here is my code
clc; clear;
pkg load symbolic
syms t tau Wn % Declare symbolic variables
f = tau^2 * sin( Wn *(t-tau) );
convolution = int( f, tau, [0 t] ); % Specify tau as the integration variable
% and integration limits are from 0 to t
pretty(convolution)
The code runs, but does not return something useful. Instead of returning an answer, it returns this:
t
⌠
⎮ 2
⎮ τ ⋅sin(Wn⋅t - Wn⋅τ) dτ
⌡
0
i.e. the original integral with the function inside of it.
I've tried troubleshooting the problem in the following ways:
Copy/pasting example code from the Octave int() help page, this works and evaluates the definite integral
Changing the integration syntax from 0, t to [0, t] this changes nothing
Making variable f and storing the function there, instead of the function being inside of int(). This changes nothing
I know the symbolic package is working, because the example code returns the correct definite integral.
Thanks.

Answer 1

You can use eval in order to "evaluate" (duh) the integral. E.g. with your code above, I get:
octave:9> eval( convolution )
ans = (sym)
⎧ 2
⎪t 2⋅cos(Wn⋅t) 2
⎪── + ─────────── - ─── for Wn > -∞ ∧ Wn < ∞ ∧ Wn ≠ 0
⎨Wn 3 3
⎪ Wn Wn
⎪
⎩ 0 otherwise
Note that if you actually 'define' some of those symbols on the workspace, then these get taken into account:
octave:10> Wn = 1; % or preferably `sym('1')` ...
octave:11> eval( convolution )
ans = (sym)
2
t + 2⋅cos(t) - 2