atanh
From cppreference.com
                    
                                        
                    
                    
                                                            
                    | Defined in header <math.h>
  | ||
| float       atanhf( float arg ); | (since C99) | |
| double      atanh( double arg ); | (since C99) | |
| long double atanhl( long double arg ); | (since C99) | |
Computes hyperbolic arc tangent of arg
| Contents | 
[edit] Parameters
| arg | - | floating point value | 
[edit] Return value
Inverse hyperbolic tangent of arg
[edit] See also
| (C99) | hyperbolic arc sine (function) | 
| (C99) | hyperbolic arc cosine (function) | 
| hyperbolic tangent (function) | |
[edit] External links
Weisstein, Eric W. "Inverse Hyperbolic Tangent." From MathWorld--A Wolfram Web Resource.