No. Check things like this by simply doing things like this:
[x,y] = meshgrid(linspace(-2,2,401));
pcolor(x,y,abs(x)+abs(y)),shading flat,colorbar
hold on
contour(x,y,abs(x)+abs(y),[1 1],'k')
That way you will see what your region of integration looks like.
HTH
