Doubling identity for sinh (1)
From specialfunctionswiki
Theorem
The following formula holds: $$\sinh(2z)=2\sinh(z)\cosh(z),$$ where $\sinh$ denotes hyperbolic sine and $\cosh$ denotes hyperbolic cosine.
Proof
References
- 1964: Milton Abramowitz and Irene A. Stegun: Handbook of mathematical functions ... (previous) ... (next): $4.5.31$