Coth of a sum

From specialfunctionswiki
Revision as of 22:42, 21 October 2017 by Tom (talk | contribs)
Jump to: navigation, search

Theorem

The following formula holds: $$\coth(z_1+z_2)=\dfrac{\coth(z_1)\coth(z_2)+1}{\cosh(z_1)+\coth(z_2)},$$ where $\coth$ denotes hyperbolic cotangent.

Proof

References