please quickly

Define = 2x2 3xy H- y, and P(2, I) be a point in R . (a) Find the direction at which f (x, y) decreases at the fastest rate at P (2, 1). (b) Find the directional derivative Dvf of f(c, y) at the point P(2, 1) in the direction v = Ai 3j. Define = 2x2 3xy H- y, and P(2, I) be a point in R . (a) Find the direction at which f (x, y) decreases at the fastest rate at P (2, 1). (b) Find the directional derivative Dvf of f(c, y) at the point P(2, 1) in the direction v = Ai 3j.