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