[Problem] A long, nonconducting, solid cylinder of radius 3.3 cm has a nonuniform volume charge density ρ that is a function of radial distance r from the cylinder axis: ρ = Ar2. For A = 3.0 µC/m5, what is the magnitude of the electric field at (a) r = 1.3cm and (b) r = 5.7cm.

[Attempt] Ok so I really don't know where to start on this problem. The equation I'm thinking about is

but I don't know how to integrate the area into all of this. I only have on attempt given to me on this problem so it kind of prohibits me from plugging and chugging and seeing what the result is, but I'm hoping I can get some help from you guys.