\[
\boxed{
{\frac {\rm d}{{\rm d}x}}y \left( x \right) -{\frac {y \left( x \right) -{x}^{2}\sqrt {{x}^{2}- \left( y \left( x \right)  \right) ^{2}}}{xy \left( x \right) \sqrt {{x}^{2}- \left( y \left( x \right)  \right) ^{2}}+x}}=0}
\]