\[
\boxed{
{\frac {\rm d}{{\rm d}x}}y \left( x \right) ={\frac {y \left( x \right)  \left(  \left( y \left( x \right)  \right) ^{2}+y \left( x \right) {{\rm e}^{bx}}+ \left( {{\rm e}^{bx}} \right) ^{2} \right) }{ \left( {{\rm e}^{bx}} \right) ^{2}}}=0}
\]