Computing the coefficient of fourier series but the code not working?

Hi guys, I am trying to find all the coefficients, bn, for n =[0,20], T = 4, and w = 2*pi/T

The exact coefficient can be found here: http://imageshack.us/photo/my-images/3/44048382.png/

I have attempted a small piece of code to solve this problem but somehow it is not working the way I would have expected it to:

syms n w t T; T = 4; n = 0:20; w = 2*pi/T; b = inline(vectorize(2/T*t*sin(n*w*t))); bn = quadl(b,-T/2,T/2)

It will be great if someone can figure out how this can be made to work. Thanks in advance.