\[
\boxed{
{\frac {\rm d}{{\rm d}x}}y \left( x \right) ={\frac { \left( a \left( y \left( x \right)  \right) ^{2}+b{x}^{2} \right) ^{2}x}{{a}^{5/2}y \left( x \right) }}=0}
\]