Compute the directional derivative of the following function at the given point P in the direction of th given vector. Be sure to use a unit vector for the direction vector. f ( x, y ) = In (4 +x2 + 3y2); P(2, -3); (1,3) The directional derivative is (Type an exact answer, using radicals as needed.) Consider the function f(x,y) = 4x2 - y2 - 8 and the point ( - 2, - 2). a. Find the unit vectors that give the direction of steepest ascent and steepest descent at P. b. Find a vector that points in a direction of no change in the function at P. a. What is the unit vector in the direction of steepest ascent at P? (Type exact answers, using radicals as needed.) What is the unit vector in the direction of steepest descent at P? (Type exact answers, using radicals as needed.) b. Which of the following vectors is in a direction of no change of the function at P? O A. (-4, 16) O B. (-4, -16) O C. (16,4) OD. (-16, -4) 1. Consider the function f(x,y) = x4 - 4x y + y2+ 9 and the point P( - 2,3) a. Find the unit vectors that give the direction of steepest ascent and steepest descent at P. b. Find a vector that points in a direction of no change in the function at P. a. What is the unit vector in the direction of steepest ascent at P? (Type exact answers, using radicals as needed.)