Arc hyperbolic cosine
[Classification]
Mathematical library
[Syntax]
#include <math.h>
double __far acosh(double x); (C99)
[Return value]
Returns the arc hyperbolic cosine of x.
If x is smaller than 1, returns a Not-a-Number (NaN) and sets macro EDOM to global variable errno.
[Description]
This function calculates the arc hyperbolic cosine of x. Specify the angle in radian.