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atanhl (3)
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.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
atanh(), atanhf(), atanhl(): _BSD_SOURCE || _SVID_SOURCE ||
_XOPEN_SOURCE >= 500 || _ISOC99_SOURCE; or cc -std=c99
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)
2007-07-26 ATANH(3)
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