catanh (3)

Leading comments

Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
and Copyright (C) 2011 Michael Kerrisk <mtk.manpages@gmail.com>

%%%LICENSE_START(GPL_NOVERSION_ONELINE)
Distributed under GPL
%%%LICENSE_END

(The comments found at the beginning of the groff file "man3/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

This page is part of release 4.04 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at www.kernel.org/doc/man-pages