Evaluate the following double integrals over the given regions:

$\displaystyle \displaystyle\int\displaystyle\int_R \dfrac{x}{\sqrt{x^2 + y^2}} $ dA

$\displaystyle R= {(x,y) | 0 < x < \sqrt{4y -y^2}, 0 < y < 2} $

I have a feeling that this is not easily intergrated, im not too sure how i would go about doing it.. help would be appreciated.

Many thanks