\[
\boxed{
{\frac {\rm d}{{\rm d}x}}y \left( x \right) =-{\frac {-y \left( x \right) +{x}^{3}\sqrt { \left( y \left( x \right)  \right) ^{2}+{x}^{2}}-{x}^{2}\sqrt { \left( y \left( x \right)  \right) ^{2}+{x}^{2}}y \left( x \right) }{x}}=0}
\]