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