Advice:
I've seen this around quite a bit. what image is it referring to? I cannot answer this because there is no image.
By the divergence theorem,
![\displaystyle\iint_S\vec F\cdot\mathrm d\vec S=\iiint_{[0,\pi/2]^3}\mathrm{div}\vec F\cdot\mathrm dV](https://tex.z-dn.net/?f=%5Cdisplaystyle%5Ciint_S%5Cvec%20F%5Ccdot%5Cmathrm%20d%5Cvec%20S%3D%5Ciiint_%7B%5B0%2C%5Cpi%2F2%5D%5E3%7D%5Cmathrm%7Bdiv%7D%5Cvec%20F%5Ccdot%5Cmathrm%20dV)
We have

Then the volume integral is

Answer:
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No one could answer this question because we cant see the picture.