NAME

asinh, acosh, atanh − inverse hyperbolic functions

SYNOPSIS

#include <math.h>

double asinh(double x);

double acosh(double x);

double atanh(double x);

DESCRIPTION

asinh(), acosh(), and atanh() return respectively the designated inverse hyberbolic sine, cosine, and tangent of their argument. 

When x is ±INFINITY , asinh() returns ±INFINITY respectively. 

When x is +INFINITY , acosh() returns +INFINITY. 

ERRORS

/lib/libm.a

asinh(), acosh() , and atanh() return NaN and set errno to EDOM when x is NaN.  In addition, a message indicating DOMAIN error is printed on the standard error output. 

acosh() also returns NaN and sets errno to EDOM if x < 1.0. 

atanh() also returns NaN and sets errno to EDOM if |x| ≥ 1.0.

These error-handling procedures can be changed with the function matherr() (see matherr(3M)).

/lib/libM.a

No error messages are printed on the standard error output. 

asinh(), acosh() , and atanh() return NaN and set errno to EDOM when x is NaN. 

acosh() also returns NaN and sets errno to EDOM if x < 1.0. 

atanh() also returns NaN and sets errno to EDOM if |x| ≥ 1.0.

These error-handling procedures can be changed by using the _matherr() function (see matherr(3M)). Note that _matherr() is provided in order to assist in migrating programs from libm.a to libM.a and is not a part of XPG3, ANSI C, or POSIX. 

DEPENDENCIES

Series 300/400

asinh(), acosh(), and atanh() are not supported on Series 300/400 systems. 

Series 700/800

asinh(), acosh(), and atanh() are not specified by any standard.  They are provided in the PA1.1 versions of the math library only.  The +DA1.1 linker option (default on Series 700 systems) links in a PA1.1 version automatically.  A PA1.1 library can also be linked in explicitly.  For more information, see the HP-UX Floating-Point Guide.

SEE ALSO

exp(3M), matherr(3M). 

Hewlett-Packard Company  —  HP-UX Release 9.0: August 1992