3.48 For the vector field E = xxz – ŷyz² – zxy, verify the divergence theorem by computing (a) the total outward flux flowing through the surface of a cube

centered at the origin and with sides equal to 2 units each and parallel to the Cartesian axes, and \text { (b) the integral of } \nabla \cdot \mathbf{E} \text { over the cube's volume. }