Suppose you apply a gauge transformation with gauge function *(x) = ike-ipºla 1 were k is an arbitrary constant to the plane wave 4-vector potential A" (1) = "(p)e-ipº la 3.1) Show that this gauge transformation has the effect of modifying E → + kph 3.2) Show that if we chose k = - we obtain the a polarization vector Po in the Coulomb gauge, ie € = 0 and Ep=0