asinh(3M)

NAME

     acosh, asinh, atanh - inverse hyperbolic functions

SYNOPSIS

     cc [ flag ... ] file ... -lm [ library ... ]
     #include <math.h>

     double acosh(double x);

     double asinh(double x);

     double atanh(double x);

DESCRIPTION

     The acosh(),  asinh()  and  atanh()  functions  compute  the
     inverse  hyperbolic cosine, sine, and tangent of their argu-
     ment, respectively.

RETURN VALUES

     The  acosh(),  asinh()  and  atanh()  functions  return  the
     inverse  hyperbolic cosine, sine, and tangent of their argu-
     ment, respectively.

     The acosh() function returns NaN and sets errno to EDOM when
     its argument is less than 1.0.

     The atanh() function returns NaN and sets errno to EDOM when
     its argument has absolute value greater than 1.0.

     The atanh() function returns _Inf and sets errno  to  ERANGE
     when its argument is _1.0.

     If x is NaN, the  asinh(),  acosh()  and  atanh()  functions
     return NaN.

     For exceptional cases, matherr(3M) tabulates the  values  to
     be returned as dictated by Standards other than XPG4.

ERRORS

     The acosh() function will fail if:

     EDOM  The x argument is less than 1.0.

     The atanh() function will fail if:

     EDOM  The x argument has an absolute value greater than 1.0.

     ERANGE
           The x argument has an absolute value equal to 1.0

ATTRIBUTES

     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|

SEE ALSO

     cosh(3M), matherr(3M),  sinh(3M),  tanh(3M),  attributes(5),
     standards(5)