Gauss's law and two point charges **
(a) Two point charges q are located at positions x = ±R. At points close to the origin on the x axis, find Ex. At points close to the origin on the y axis, find Ey. Make suitable approximations with x « R and y « R.
(b) Consider a small cylinder centered at the origin, with its axis along the x axis. The radius is r0 and the length is 2x0. Using your results from part (a), verify that there is zero flux through the cylinder, as required by Gauss's law.