In Problems 21 - 24 find the average value of each function over the given rectangle.
22.
f(x,y) = x2 + y2;
R = {(x,y)| -1 ≤ x ≤ 2, 1 ≤ y ≤ 4}
24.
f(x,y) = x2y3;
R = {(x,y)} -1 ≤ x ≤ 1, 0 ≤ y ≤ 2