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