- 17. Evaluate ff Finds, where F . 4xzl - y' ) + yck and $ is the surface of the cube bounded by x -0. x =1, y=0. y=1, = =0, z=1. By the divergence theorem, the required integral is equal to SSS (4 -)av . (42 -y) dz dy dx (2-y) dydx - The surface Integral may also be evaluated directly as in Problem 23. Chapter 5