please solve this problem

9 ) Consider the function f (x, y) = * 2 a. Evaluate f(2,5) and f (1.9, 5.2) and calculate Az. Round your answers to three decimal places. f ( 2, 5 ) = f (1.9, 5.2) = AZ = b. State the total differential symbolically using partial derivatives and differentials. dz = c. Calculate the total differential dz to approximate Az by substituting for x, y, dx, dy in part b. dz = d. Use dz to approximate f (1.9, 5.2) f (1.9, 5.2) ~ f (2, 5) + dz so f (1.9, 5.2) ~ e. How close is this estimate of f(1.9, 5.2) to the actual value of f (1.9, 5.2)