Let

(a) Show that the mapping u = xy, v = x − y maps D to the rectangle R = [2, 4] × [0, 3].
(b) Compute ∂(x, y)/∂(u, v) by first computing ∂(u, v)/∂(x, y).
(c) Use the Change of Variables Formula to show that I is equal to the integral of f (u, v) = v over R and evaluate.

I = (x - y) dx dy, where