## Linux and UNIX Man Pages

Test Your Knowledge in Computers #924
Difficulty: Medium
The present form of UTC, with leap seconds, is only defined starting from 1 January 1972.
True or False?

# atanhf(3) [freebsd man page]

```ATANH(3)						   BSD Library Functions Manual 						  ATANH(3)

NAME
atanh, atanhf, atanhl -- inverse hyperbolic tangent functions

LIBRARY
Math Library (libm, -lm)

SYNOPSIS
#include <math.h>

double
atanh(double x);

float
atanhf(float x);

long double
atanhl(long double x);

DESCRIPTION
The atanh(), atanhf(), and atanhl() functions compute the inverse hyperbolic tangent of the real argument x.  For a discussion of error due
to roundoff, see math(3).

RETURN VALUES
These functions return the inverse hyperbolic tangent of x if successful.	If the argument has absolute value 1, a divide-by-zero exception
is raised and an infinity is returned.  If |x| > 1, an invalid exception is raised and an NaN is returned.

acosh(3), asinh(3), exp(3), fenv(3), math(3)

HISTORY
The atanh(), atanhf(), and atanhl() functions appeared in 4.3BSD, FreeBSD 2.0, and FreeBSD 10.0, respectively.

BSD								   June 9, 2013 							       BSD```

## Check Out this Related Man Page

```ATANH(3)						   BSD Library Functions Manual 						  ATANH(3)

NAME
atanh -- inverse hyperbolic tangent function

SYNOPSIS
#include <math.h>

double
atanh(double x);

long double
atanhl(long double x);

float
atanhf(float x);

DESCRIPTION
The atanh() function computes the inverse hyperbolic tangent of the real argument x.

SPECIAL VALUES
atanh(+-0) returns +-0.

atanh(+-1) returns +-infinity and raises the "divide-by-zero" floating-point exception.

atanh(x) returns a NaN and raises the "invalid" floating-point exception for |x| > 1.

VECTOR OPERATIONS
If you need to apply the atanh() function to SIMD vectors or arrays, using the following functions provided by the Accelerate.framework may
give significantly better performance:

#include <Accelerate/Accelerate.h>

vFloat vatanhf(vFloat x);
void vvatanhf(float *y, const float *x, const int *n);
void vvatanh(double *y, const double *x, const int *n);

acosh(3), asinh(3), exp(3), math(3)

STANDARDS
The atanh() function conforms to ISO/IEC 9899:2011.

4.3 Berkeley Distribution					 December 11, 2006					 4.3 Berkeley Distribution```

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