\[
\boxed{
 \left(  \left( {\frac {\rm d}{{\rm d}x}}y \left( x \right)  \right) ^{2}+1 \right)  \left( \sin \left( x{\frac {\rm d}{{\rm d}x}}y \left( x \right) -y \left( x \right)  \right)  \right) ^{2}-1=0}
\]