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);

SEE ALSO

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

STANDARDS

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