Integration問題!help!

doneonex

1. Evaluate the integral


                  ∫∫D (x^2+y^2)dxdy
where D is the area between the circles x^2 + y^2 = 4 and x^2 + y^2 +2x = 0.


2. Evaluate:

                ∫∫R  ln(x^2 + y^2)/sqrt(x^2 + y^2) dydx
                    

where R is the region inside x^2 + y^2 = 1 and bounded by y = 0 and y = x

by transforming into plane polar coordinates.




3. Find the volume enclosed by the parabolic cylinder y = x^2 and the planes

z = 0 and x + y + z = 2.



4. Find the volume remaining when the hemisphere x^2 + y^2 + z^2 = a^2 is cut

by the cylinder x^2 + y^2 = ax.