(1 point) Find the directions in which the given function f (x, y, z) increases and decreases most rapidly at the given point. Then find the derivatives of the function in these directions. f (x, y, z) = xe\" + Z3 and the point is (3,111(2), 4). The direction of greatest increase is (Answer with a unit vector in the format .) The derivative of the function in this direction is The direction of greatest decrease is (Answer with a unit vector in the format .) The derivative of the function in this direction is