Hyperbolic cosine

[Classification]

Mathematical library

[Syntax]

#include <math.h>

long double __far coshl(long double x); (C99)

[Return value]

Returns the hyperbolic cosine of x.

coshl returns ∞ and sets macro ERANGE to global variable errno if an overflow occurs.

[Description]

This function calculates the hyperbolic cosine of x. Specify the angle in radian. The definition expression is as follows.

(e x + e -x) / 2