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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

       The   catanh()   function  calculates  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.

CONFORMING TO

       C99.

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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       project, and information about reporting bugs, can be found at  http://man7.org/linux/man-
       pages/.

                                            2011-09-15                                  CATANH(3)