In a certain region, the electric field is given by D = 2(z + l)cos a

In a certain region, the electric field is given by
D = 2ρ(z + l)cos Φ aρ – ρ(z + l)sin Φ aΦ + ρ2 cos Φ az µC/m2
(a) Find the charge density.
(b) Calculate the total charge enclosed by the volume 0 < ρ < 2, 0 < Φ < π/2, 0 < z < 4.
(c) Confirm Gauss's law by finding the net flux through the surface of the volume in (b).