CATANH(3)						     Linux Programmer's Manual							 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

       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>
", argv[0]);
	       exit(EXIT_FAILURE);
	   }

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

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

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

	   exit(EXIT_SUCCESS);
       }

SEE ALSO

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

COLOPHON

       This page is part of release 3.44 of the Linux man-pages project.  A description of the project, and information about reporting bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

								    2011-09-15								 CATANH(3)