QUESTION 1 For the function f (x.y) =9-42y + 2xy - 2x2 - 4y2 find the partial derivative with repect to x, f 2y -4X 2xy - 4X 0 2y - 272 2x - 4 QUESTION 2 For the function f (x.y) =9-42x+ 2x - 2x2- 4y2 find the partial derivative with repect to y, f 0 -424 2x - 8y 2xy - By 2X - 4y2 0 -42y - 8y QUESTION 3 Find the critical point for the function f (x. y ) =9- 42y + 2ty - 212-42 O X= - 3. )= -6 x -3, y =6 x -6. y-3 x =6, y= -3 QUESTION 4 For the function f (x.y) =9-42y + 2xy -2x2-4y2 evaluate the second order partial derivative, jf at the critical point. O O