Here is the promblem

Divergence Theorem which i really don't understand well is

I went ahead and got the gradient vector which is

and then the function i got when i set up the triple integral is

and i guess all that is left for me to do is to set up and integrate. Math experts am im right up until this part, and if i am help me set up the triple integral. I'm assuming i have to switch to polar coordinates, i hope i don't have to switch to spherical or cylindrical coordinates, because i really don't understand that stuff very well!