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