In the cartesian coordinates we proved the divergence theorem in the class by taking the divergence of any vector and then finding the volume integral

and then finding the flux throught six faces of the cube and then adding all. which gives LHS=RHS

Now in cylindrical coordinates i dont know what to take for the flux, i mean which surfaces??? i dont know for which surfaces of the cylinder i have to calculate flux and then add all of them. Please guide me?

we have been given limits for row, phi and z and S IS THE SURFACE OF A WEDGE!