asinh(3)asinh(3)NAME
asinh, acosh, atanh - Compute inverse hyperbolic functions
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 );
LIBRARY
Math Library (libm)
STANDARDS
Interfaces documented on this reference page conform to industry stan‐
dards 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 excep‐
tional arguments:
────────────────────────────────────────────────────
Function Exceptional Argument Routine Behavior
────────────────────────────────────────────────────
asinh() None N/A
asinhf() None N/A
asinhl() None N/A
acosh() x<1 Invalid argument
acoshf() x<1 Invalid argument
acoshl() x<1 Invalid argument
atanh() x>1 or x=1 Invalid argument
atanhf() x>1 or x=1 Invalid argument
atanhl() x>1 or x=1 Invalid argument
────────────────────────────────────────────────────
asinh(3)