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