Consider the double integral xdA where R = {(x,y) R(x-4) y 4}. (a) Make a neat, labelled sketch of the region R in the ry-plane. (b) Express this double integral as an integral with respect to y first, then z a dy dr rather than a dA, with correct limits of integration. that is using (c) Express this double integral as an integral with respect to a first, then y that is using a dx dy rather than a dA, with correct limits of integration (reversing the order of integration compared to (b) above). (d) Evaluate this double integral using either your answer to (b) or (c).