## Linux and UNIX Man Pages

Test Your Knowledge in Computers #614
Difficulty: Medium
In Python, strings in double quotes work exactly the same way as strings in single quotes.
True or False?

# asinh(3) [osf1 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)```

## Check Out this Related Man Page

```ACOSH(3)						     Linux Programmer's Manual							  ACOSH(3)

NAME
acosh, acoshf, acoshl - inverse hyperbolic cosine function

SYNOPSIS
#include <math.h>

double acosh(double x);
float acoshf(float x);
long double acoshl(long double x);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

acosh():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| _XOPEN_SOURCE >= 500
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
acoshf(), acoshl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION
These functions calculate the inverse hyperbolic cosine of x; that is the value whose hyperbolic cosine is x.

RETURN VALUE
On success, these functions return the inverse hyperbolic cosine of x.

If x is a NaN, a NaN is returned.

If x is +1, +0 is returned.

If x is positive infinity, positive infinity is returned.

If x is less than 1, a domain error occurs, and the functions return a NaN.

ERRORS
See math_error(7) for information on how to determine whether an error has occurred when calling these functions.

The following errors can occur:

Domain error: x is less than 1
errno is set to EDOM.  An invalid floating-point exception (FE_INVALID) is raised.

ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).

+-----------------------------+---------------+---------+
|Interface		     | Attribute     | Value   |
+-----------------------------+---------------+---------+
|acosh(), acoshf(), acoshl()  | Thread safety | MT-Safe |
+-----------------------------+---------------+---------+
CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.

The variant returning double also conforms to SVr4, 4.3BSD.