let F = (x^2+y^2+z^2)^n * (xi+yj+zk) for F, i, j, k vectors
and let Omega be the sphere of radius b centered on the origin
i) calculate the outward flux of F across the boundary dOmega
ii) calculate the divergence of F
iii) referring to (i) and (ii), what is special about the value n = -3/2?