1. The problem statement, all variables and given/known data I'm trying to find the fourier series of x/3. 2. Relevant equations 3. The attempt at a solution So i believe that it is an odd function so a0, ak = 0. To find bk: bk = 1/3pi int (x sin kx dx) from -pi to pi. From integration by parts = 1/3pi ([x sin kx from -pi to pi]+ 1/k int (cos kx dx) from -pi to pi) = 1/3pi [(pi sin k pi + pi sin -k pi) +1/k^2 (sin k pi - sin -k pi)] I think that works out to be 0? Is that right?