(1 point) Find the directions in which the given function f (x, 32) increases and decreases most rapidly at the given point. Then find the derivatives of the function in these directions. f(x, y) = x2 + xy + 6y2 and the point is (1, 9). 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