A contour map is shown for a function f(@, y) on the rectangle R = [ - 3, 6] x [ - 1, 4]. y A 3 To 2 6 10 12 14 12 16 3 18 X a. Use the midpoint rule with m = 3 and n = 2 to estimate the value of f(x, y) d.A. b. Estimate the average value of the function f(x, y). fave ~ Hint Divide the region into six rectangles, and use the contour lines to estimate the values for f(x, y)