catanh(3)

NAME

   catanh, catanhf, catanhl - complex arc tangents hyperbolic

SYNOPSIS

   #include <complex.h>

   double complex catanh(double complex z);
   float complex catanhf(float complex z);
   long double complex catanhl(long double complex z);

   Link with -lm.

DESCRIPTION

   These  functions calculate the complex arc hyperbolic tangent of z.  If
   y = catanh(z), then z = ctanh(y).  The imaginary part of y is chosen in
   the interval [-pi/2,pi/2].

   One has:

       catanh(z) = 0.5 * (clog(1 + z) - clog(1 - z))

VERSIONS

   These functions first appeared in glibc in version 2.1.

ATTRIBUTES

   For   an   explanation   of   the  terms  used  in  this  section,  see
   attributes(7).

   
   Interface                       Attribute      Value   
   
   catanh(), catanhf(), catanhl()  Thread safety  MT-Safe 
   

CONFORMING TO

   C99, POSIX.1-2001, POSIX.1-2008.

EXAMPLE

   /* Link with "-lm" */

   #include <complex.h>
   #include <stdlib.h>
   #include <unistd.h>
   #include <stdio.h>

   int
   main(int argc, char *argv[])
   {
       double complex z, c, f;

       if (argc != 3) {
           fprintf(stderr, "Usage: %s <real> <imag>\n", argv[0]);
           exit(EXIT_FAILURE);
       }

       z = atof(argv[1]) + atof(argv[2]) * I;

       c = catanh(z);
       printf("catanh() = %6.3f %6.3f*i\n", creal(c), cimag(c));

       f = 0.5 * (clog(1 + z) - clog(1 - z));
       printf("formula  = %6.3f %6.3f*i\n", creal(f2), cimag(f2));

       exit(EXIT_SUCCESS);
   }

SEE ALSO

   atanh(3), cabs(3), cimag(3), ctanh(3), complex(7)

COLOPHON

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                              2015-04-19                         CATANH(3)

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