\[
\boxed{
{\frac {\rm d}{{\rm d}x}}y \left( x \right) ={\frac { \left(  \left( {x}^{2}+1 \right) ^{3/2}{x}^{2}+ \left( {x}^{2}+1 \right) ^{3/2}+ \left( y \left( x \right)  \right) ^{2} \left( {x}^{2}+1 \right) ^{3/2}+{x}^{2} \left( y \left( x \right)  \right) ^{3}+ \left( y \left( x \right)  \right) ^{3} \right) x}{ \left( {x}^{2}+1 \right) ^{3}}}=0}
\]