2. Find the maximum and minimum values of the function f (x, y, z) = on the region -f- -F z2 1. (Note that f (x, y, z) = O as soon as at leiLst, one of y, or z is O. Since we can see that f both negative and positive values, main and max cannot occur at any such points, so we can assume that O, y O, and z O.)