Two point electric dipoles are crossed in the x-y plane as shown below (at left). Both oscillate

Question:

Two point electric dipoles are crossed in the x-y plane as shown below (at left). Both oscillate at frequency ω but with a π/2 phase difference.
(a) Sketch the time evolution of the instantaneous angular distribution of power in the x-y plane at several representative times between t = 0 and t = 2π/ω.
(b) Show that the radiation emitted along the z-axis is circularly polarized. Is the polarization the same for +z as it is for −z?
(c) Show that two crossed dipoles oscillating at frequency ω with no phase difference between them also emit circular polarized radiation along the z-axis if they are displaced by λ/4 as shown below (at right). Is the polarization the same for z as it is for −z?