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