$$I\int_{0}^{2}\sqrt{n^{2}-x^{2}}dx$$
$\frac{I\left(n^{2}\arctan(\frac{2}{\sqrt{n^{2}-4}})+2\sqrt{n^{2}-4}\right)}{2}$
$|n|\geq |x|$
$\frac{n^{2}\arctan(\frac{2}{\sqrt{n^{2}-4}})+2\sqrt{n^{2}-4}}{2}$
$|n|\geq |x|$
