\[
\boxed{
{\frac {\rm d}{{\rm d}x}}y \left( x \right) ={\frac {\cosh \left( x \right) }{\sinh \left( x \right) }}+{\it \_F1} \left( y \left( x \right) -\ln  \left( \sinh \left( x \right)  \right)  \right) =0}
\]