ATANH function
    ATANH(Number) ATANH(Number)
  
  Number
        Number or { Number }
      
      The input number.
Returns
        Number or { Number }
      
      The inverse hyperbolic tangent.
Returns the inverse hyperbolic tangent of a number.
Example
      ATANH(0.76159416)ATANH(0,76159416)
      
    
    Returns roughly 1.