\[
\boxed{
{\frac {\rm d}{{\rm d}x}}y \left( x \right) +a \left( {\frac {\rm d}{{\rm d}x}}\phi \left( x \right)  \right)  \left( y \left( x \right)  \right) ^{3}+6\,a\phi \left( x \right)  \left( y \left( x \right)  \right) ^{2}+{\frac { \left( 2\,a+1 \right) y \left( x \right) {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}\phi \left( x \right) }{{\frac {\rm d}{{\rm d}x}}\phi \left( x \right) }}+2\,a+2=0}
\]