∫D∫xdxdy
=∫(1,2)xdx∫(1/x,x)dy
=∫(1,2)x(x-1/x)dx
=∫(1,2)(x^2-1)dx
=[x^3/3-x]|(1,2)
=(8/3-2)-(1/3-1)
=4/3