ATANH(3) Linux Programmer s Manual ATANH(3)

NAME atanh, atanhf, atanhl - inverse hyperbolic tangent function

SYNOPSIS #include <math.h>

double atanh(double x); float atanhf(float x); long double atanhl(long double x);

Link with -lm.

DESCRIPTION The atanh() function calculates the inverse hyperbolic tangent of x; that is the value whose hyperbolic tangent is x. If the absolute value of x is greater than 1.0, atanh() returns not-a-number (NaN) and errno is set.

ERRORS EDOM x is out of range.

CONFORMING TO SVr4, POSIX.1-2001, 4.3BSD, C89. The float and long double variants are C99 requirements.

SEE ALSO acosh(3), asinh(3), catanh(3), cosh(3), sinh(3), tanh(3)

2002-07-27 ATANH(3)