A slab of insulating material has a non-uniform positive charge density = Cx2, where x is measured from the center of the slab as shown in the figure...

A slab of insulating material has a non-uniform positive charge density  = Cx2, where x is measured from the center of the slab as shown in the figure and C is a constant. The slab is infinite in the y and z directions. Derive expressions for the electric field in (a) the exterior regions (|x| > d/2) and (b) the interior region of the slab (|x| < d/2)