Consider a uniformly charged sphere of radius R1 with a spherical hole of radius R2 displaced a distance x0 from the center. Let ρ be the charge density.
a) What is E on the x axis as a function of x?
b) What is E on the y axis as a function of y?
(Hint: The superposition of two spheres of radii R1 and R2 and of equal and opposite charge densities has the same solution).