Two spheres with radius R have uniform but equal and opposite charge densities . The centers of the two spheres fail to coincide by an

Two spheres with radius R have uniform but equal and opposite charge densities ±ρ. The centers of the two spheres fail to coincide by an infinitesimal displacement vector δ. Show by direct superposition that the electric field produced by the spheres is identical to the electric field produced by a sphere with a suitably chosen uniform polarization P.