Let D = (2, y ) : 2 6 - S By2, . Let f(z, y) = y2x. In this exercise, we will evaluate f (x, y) d.A. D 1 . The most natural change of variables to make is to set u = u(x, y) = and v = v(x, y) = xy2 . The inverse transformation is a = (u, v) = , and y = y(u, v) = a(x, y) . The Jacobian is a(u, v) . Putting the above together, we get / f(x, y)dA = dudv = D