C/math.h/atanh

atanh: returns the arc hyperbolic tangent of arg

<source lang="cpp">

//Declaration: float atanhf(float arg);

              double atanh(double arg); 
              long double atanhl(long double arg);  

//Parameter: This argument must be in the range -1 to 1.

 #include <math.h>
 #include <stdio.h>
 int main(void)
 {
   printf("%f.\n",  atanh(12));
   return 0;
 }
        

/* -1.#IND00.

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      </source>