# ATANH

Elemental Intrinsic Function (Generic): Produces the hyperbolic arctangent of x.

result = ATANH (x)

x | (Input) Must be of type real, where | x | is less than or equal to 1, or of type complex.

## Results

The result type and kind are the same as x.

If the result is real, it lies in the range -1.0 < ATANH (x) < 1.0.

If the result is complex, the imaginary part is expressed in radians and lies in the range –pi/2 <= AIMAG (ATANH (x)) <= pi/2.

Specific Name | Argument Type | Result Type
--- | --- | ---
ATANH | REAL(4) | REAL(4)
DATANH | REAL(8) | REAL(8)
QATANH | REAL(16) | REAL(16)

## Example

ATANH (-0.77) has the value -1.02033.

ATANH (0.5) has the value 0.549306.

Parent topic: A to B