Below is a set of level curves for a function f(x,y) with the heights of each curve indicated. yo 1 2 (a) Use this graph to estimate fr(2, 2). CC 3 8 9 10 (c) Draw Vf(2, 2) on the set of level curves. 7 5 9 (b) Use this graph to estimate f, at (1,2), (2, 2), and (3, 2). (d) Use your answers from (b) to determine whether the second-order partial de- rivative fyz is positive or negative at (2,2). Hint: z increases for each of your answers for fy, and fyr measures how fy changes as r increases. Please use complete sentences to explain your answer.