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