The vercosine, written 
and also known as the "versed cosine," is a little-used trigonometric function
defined by
 |  |  |
(1)
|
 |  |  |
(2)
|
where 
is the cosine.
Vercosine
See also
Covercosine, Coversine, Excosecant, Exsecant, Hacovercosine, Hacoversine, Havercosine, Haversine, VersineExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Vercosine." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Vercosine.html