Finding the flux of an electrix field

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Homework Statement



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?

Homework Equations



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!
 

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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
 

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