(PHP 4 >= 4.1.0, PHP 5)
atanh — Inverse hyperbolic tangent
$arg
    )
   Returns the inverse hyperbolic tangent of
   arg, i.e. the value whose
   hyperbolic tangent is arg.
  
arg
     The argument to process
   Inverse hyperbolic tangent of arg 
  
| Version | Description | 
|---|---|
| 5.3.0 | This function is now available on all platforms |