The havercosine, also called the haversed cosine, is a little-used trigonometric function defined by havercos z | congruent | vercos z | = | 1/2(1 + cos z), where vercos z is the vercosine and cos z is the cosine.
covercosine | coversine | excosecant | exsecant | hacovercosine | hacoversine | haversine | vercosine | versine