1. Given the function f(x,y) = X3 y2 + 4xy 16x + 6y + 9, find the following: (a) Write out all first and second order derivatives of f(x, y) and notate them correctly. (b) Find the critical point(s) of the function. For full credit, show all the algebra to find these or explain in detail how you use your calculator to find them. Give your answer as ordered pairs (a, b). (c) Find the determinant, D(a,b), for each critical point (a, b). Then classify each critical point as a saddle point, relative minimum, or relative maximum point