how to find fourier coefficients an and bn?

hi guys, i want to know if someone can help me with this code, the thing is that i want to calculate the coefficients of a fourier transform, i made this code with an example that my teacher of university give me, but the thing is that the result is wrong an is very weird because with other examples the program works good, but especially with this example the program give me wrong results for an and bn. can someone help me to know what's wrong? pleasseee. and thanks.

this is the example:

 and this is the code:

close all
  clc
  syms t n
  pi=3.1416;

A = [-pi 0 pi]; %intervalos
f = [-1 2]; %funciones

f = sym(f);
T = max(A)-min(A);
wo = 2*pi/(T);

Ao = 0;
for i=1:length(f)
    Ao = Ao +int(f(i), A(i), A(i+1));
end
Ao =(2*Ao/T)

An = 0;
syms n t pi
for i=1:length(f)      

      An = An + int(f(i)*cos(n*wo*t), A(i), A(i+1))
  end

Bn = 0;
for i=1:length(f)
    Bn = Bn + int(f(i)*sin(n*wo*t), A(i), A(i+1));
end
Bn = simple(2*Bn/T)