Let z =f(x,y) = (y x)2 a) Evaluate the partial derivative fy(1, 2). Enter your answer in the blank below. b) Find the contour corresponding to z=1. Express the contour as yin terms of x. c) On your solution sheet, draw xy axes, and then draw the contours of f(X,y) corresponding to z = O, 1, 2, 3, 4. Clear label the axes, and indicate the scale. Also indicate clearly which contour curve is associated with which 2 value. Your Answer: :]