16. An airplane is flying in the sky. At t = 0, it is at position (-1, 2, 10), at t = 0.1, it is at posi (-2, 4, 11), and at t = 0.25, it is at position (-2, 3, 15). (a) Approximate the velocity at two points in the airplane's flight. (b) Approximate the acceleration of the airplane