Been working my way thru H.M. Schey-been out of college for 50 yrs. This problem has me stumped. F (of x,y,z)= i (f of x) + j (f of y)+k f (-2z). F is a vector function, and i,j,k are unit vectors for x,y,z axis. The problem is to find Div F., and then show it is 0 for the point c,c, -c/2. Cannot for the life of me see how one can get a unique solution that would allow one to insert the point c,c, -c/2, which are for x,y,z. What am I missing, please and thanks. Jim L.