Evaluate the surface integral F . ds for the given vector field F and the oriented surface S. In other words, find the flux of F across S. For closed surfaces, use the positive (outward) orientation. F (x, y, z) = xi +yj+ 6k S is the boundary of the region enclosed by the cylinder x- + z 0 and where div(F) 0 for y -X O div(F) > 0 for y > x; div(F) 0 for y > -x; div(F) 0 for y x Calculate div(F) to check your guess. div(F) =