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





NAME
       atanh, atanhf, atanhl - inverse hyperbolic tangent func-
       tion

SYNOPSIS
       #include <math.h>

       double atanh(double x);

       float atanhf(float x);

       long double atanhl(long double x);


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,
       acosh() returns not-a-number (NaN) and errno is set.

ERRORS
       EDOM   x is out of range.

CONFORMING TO
       SVID  3,  POSIX,  BSD 4.3, ISO 9899.  The float and long
       double variants are C99 requirements.

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



                           2002-07-27                  ATANH(3)
