Electric field inside a charged insulator

[Oblivion77]

Homework Statement

Homework Equations

EA = Qenclosed / epsilon

The Attempt at a Solution

I found the electric field outside to be $$\rho*d/2\epsilon_{0}$$. Not sure if that helps, I don't know what to do since it says "as a function of x"

 

[LowlyPion]

You know it's going to be linear from x = 0 to x = d/2, and at d/2 you know what it is and at 0 it's 0. So ...

 

[Oblivion77]

Hmm i am not sure I follow. I understand its linear from x = 0 to x = d/2 and at d/2 its the same as Eout?

 

[LowlyPion]

That's what it looks like to me.

So what equation expresses that?