ATANH function
ATANH returns the inverse hyperbolic tangent of a number.
Syntax
ATANH (number)
This function returns the inverse hyperbolic tangent of number, which is the value whose hyperbolic tangent is Number. The Number must be between -1 and 1 (excluding -1 and 1).
Example
=ATANH(0.76159416) returns 1.
=ATANH(-0.1) returns -0.10034.