Q10. Consider the following function. f(x, y) = xy (x, y) # (0,0) 0 (x, y) = (0,0) of (r, y) and of (a) Compute ay (x y) for (x, y) # (0, 0). (b) Give simple expressions for " (0, y) and of dy (x, 0) when z, y # 0. a2 f (c) Find the second-order partial derivatives (0, 0) and (0, 0). axdy (d) Oh no! The mixed-partials in part (c) are not equal! Explain how this does NOT contradict the equality of mixed partials