1. The problem statement, all variables and given/known data Jackson 6.4b 2. Relevant equations Multipole expansion especially Eq 4.9 in Jackson which is for a Quadrupole 3. The attempt at a solution I found the result in 6.4a. The rho over there tells us that there is a charge density inside the sphere. Since the charge density is uniform about the x,y and z axis hence the dipole part of the expansion will go to zero. Now for the quadrupole Q33: I convert the formula 4.9 to spherical coordinates and integrate the resulting expression: (3z^2 - r^2 )*r^2 dr * d(Cos theta) * d(phi). I get 0 because of the Cos thing. I think I need something like 5/3 from the Cosine to make the answer correct.