Consider, again, the function from problem 1, z = f(x, y) = 1000 1 + (x/10)2 + (y/40)2 , (a) find ∂f ∂x. (b) evaluate fx(20, 0). (c) find ∂f ∂y . (d) evaluate fy(0, 20). (e) do the values you obtained in parts (b) and (d) contradict your answer to problem 1, part (d)? explain briefly. (f) recall that this function can be thought of as a mountain. if x, y, and z all have units of feet, what are the units of ∂z/∂x and ∂z/∂y? (g) using the units from part (f), can you attach a physical meaning to the numbers you obtained in parts (b) and (d)? (h) without actually computing it, describe in words what ∂ 2f /∂x2 represents in terms of the mountain?