Nonuniform volume charge density

[shinobi12]

Homework Statement

A slab of insulating material has a nonuniform volume charge density
given by rho = Cx2, where C is a positive constant and x is measured from the slab’s center. The slab is infi…nite in the y and z directions.

(a) Find the electric fi…eld for |x| > d=2, that is, in the regions exterior to the slab.
(b) Find the electric …field for |x| < d=2, that is, in the interior region of the slab.

Homework Equations

Not sure

The Attempt at a Solution

I tried thinking in terms of gauss' law but I'm term how to tackle this problem

 

[gabbagabbahey]

Gauss' Law sounds good...what kind of symmetry does this problem possess? What type of Gaussian surface do you use when that type of symmetry is present?