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