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