atanh

Syntax

#include <math.h> double atanh(double x);

Description

This function computes the inverse hyperbolic tangent of x.

Return Value

The inverse hyperbolic tangent of x. If the the value of x is plus or minus 1, the return value is an Inf with the same sign as the argument x, and errno is set to ERANGE. If the absolute value of x is greater than 1, the return value is NaN and errno is set to EDOM.

Portability

ANSI/ISO C	No
POSIX	No