atanh
From cppreference.com
                    
                                        
                    
                    
                                                            
                    |   Defined in header <math.h>
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|   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)  | |
|   C++ documentation for atanh 
 | |
[edit] External links
Weisstein, Eric W. "Inverse Hyperbolic Tangent." From MathWorld--A Wolfram Web Resource.