Finding the flux of an electrix field

failexam

1. The problem statement, all variables and given/known data

A charge q sits in the back corner of a cube, as shown in the attachment. What is the flux of E through the shaded side?

2. Relevant equations

3. The attempt at a solution

I know that I need the surface integral of E over the shaded area, but the problem is with choosing the proper coordinates and the origin.

Please help out this poor guy!

Attached Thumbnails

 

Daniiel

Gauss's law finds the charge ENCLOSED,

So one way to do this question is to enclose the charge by surrounding the charge by another 7 boxes.

Then you can compute the integral as the charge is now enclosed.

There will be 24 faces after surrounding the charge, so integral will produce a flux 24 times the flux through one face (seeing as you only need the flux through one face) and I think you can take it from there,

I've seen this question in griffiths electrodynamics before I think