\[
\boxed{
{\frac {\rm d}{{\rm d}x}}y \left( x \right) =-1/2\,{\frac { \left( y \left( x \right)  \right) ^{2} \left( {x}^{2}y \left( x \right) -2\,x-2\,xy \left( x \right) +y \left( x \right)  \right) }{ \left( -2+xy \left( x \right) -2\,y \left( x \right)  \right) x}}=0}
\]