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