\[
\boxed{
{\frac {\rm d}{{\rm d}x}}y \left( x \right) =1/2\,{\frac {2\,{x}^{2}\cos \left( x \right) +2\,\sin \left( x \right) {x}^{3}-2\,x\sin \left( x \right) +2\,x+2\,{x}^{2} \left( y \left( x \right)  \right) ^{2}-4\,y \left( x \right) \sin \left( x \right) x+4\,y \left( x \right) \cos \left( x \right) {x}^{2}+4\,xy \left( x \right) +3-\cos \left( 2\,x \right) -2\,\sin \left( 2\,x \right) x-4\,\sin \left( x \right) +{x}^{2}\cos \left( 2\,x \right) +{x}^{2}+4\,\cos \left( x \right) x}{{x}^{3}}}=0}
\]