NAME

asinh, acosh, atanh − Compute inverse hyperbolic functions

LIBRARY

Math Library (libm.a)

SYNOPSIS

#include <math.h>

double asinh  (double x);
float  asinhf (float  x);
long double asinhl     (long double x);
double acosh  (double x);
float  acoshf (float  x);
long double acoshl     (long double x);
double atanh  (double x);
float  atanhf (float  x);
long double atanhl     (long double x);

STANDARDS

Interfaces documented on this reference page conform to industry standards as follows:

asinh():  XPG4−UNIX

acosh():  XPG4−UNIX

atanh():  XPG4−UNIX

Refer to the standards(5) reference page for more information about industry standards and associated tags. 

DESCRIPTION

The asinh(), asinhf(), and asinhl() functions return the hyperbolic arc sine of x, in the range [−infinity, +infinity] where asinh(x) = ln(x + sqrt(x∗∗2 + 1)).  The asinh() function is the inverse function of sinh() where asinh(sinh(x)) = x. 

The acosh(), acoshf(), and acoshl() functions return the hyperbolic arc cosine of x, in the range [1, +infinity] where acosh(x) = ln(x + sqrt(x∗∗2 − 1)).  The acosh() function is the inverse function of cosh() where acosh(cosh(x)) = |x|. 

The atanh(), atanhf()  and atanhl() functions return the hyperbolic arc tangent of x, in the range (−1, 1).  The atanh() function is the inverse function of tanh() where atanh(tanh(x)) = x. 

The following table describes function behavior in response to exceptional arguments: