Gauss's law for a moving charge **
Verify that Gauss's law holds for the electric field in Eq. (5.15). That is, verify that the flux of the field, through a sphere centered at the charge, is q/ϵ0. Of course, we used this fact in deriving Eq. (5.15) in the first place, so we know that it must be true. But it can't hurt to double check. You'll want to use a computer or the integral table in Appendix K.