Simpson's Formulas/Hyperbolic Sine by Hyperbolic Sine

Theorem

 * $\sinh x \sinh y = \dfrac {\cosh \paren {x + y} - \cosh \paren {x - y} } 2$

where $\sinh$ denotes hyperbolic sine and $\cosh$ denotes hyperbolic cosine.

Also presented as
This result can also be seen presented as:


 * $2 \sinh x \sinh y = \cosh \paren {x + y} - \cosh \paren {x - y}$