## Linux and UNIX Man Pages

Test Your Knowledge in Computers #48
Difficulty: Easy
Alan Turing is considered to be the 'Father of Cryptography'.
True or False?

# asinh(3m) [bsd man page]

```ASINH(3M)																 ASINH(3M)

NAME
asinh, acosh, atanh - inverse hyperbolic functions

SYNOPSIS
#include <math.h>

double asinh(x)
double x;

double acosh(x)
double x;

double atanh(x)
double x;

DESCRIPTION
These functions compute the designated inverse hyperbolic functions for real arguments.

ERROR (due to Roundoff etc.)
These  functions inherit much of their error from log1p described in exp(3M).  On a VAX, acosh is accurate to about 3 ulps, asinh and atanh
to about 2 ulps.  An ulp is one Unit in the Last Place carried.

DIAGNOSTICS
Acosh returns the reserved operand on a VAX if the argument is less than 1.

Atanh returns the reserved operand on a VAX if the argument has absolute value bigger than or equal to 1.

math(3M), exp(3M), infnan(3M)

AUTHOR
W. Kahan, Kwok-Choi Ng

4.3 Berkeley Distribution					   May 12, 1986 							 ASINH(3M)```

## Check Out this Related Man Page

```asinh(3)						     Library Functions Manual							  asinh(3)

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

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:

---------------------------------------------------
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
---------------------------------------------------
delim off

asinh(3)```