catanh(3) Linux Man Page - System Grab Bag

Name

catanh, catanhf, catanhl - complex arc tangents hyperbolic

Library

Math library ( libm ", " -lm )

Synopsis

#include <complex.h> 
double complex catanh(double complex  z );
float complex catanhf(float complex  z );
long double complex catanhl(long double complex  z );

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))

Attributes

For an explanation of the terms used in this section, see attributes(7). allbox; lbx lb lb T{ catanh()catanhf()catanhl()

Interface	Attribute	Value
T}	Thread safety	MT-Safe

Standards

C11, POSIX.1-2008.

History

glibc 2.1. C99, POSIX.1-2001.

Examples

/* Link with "-lm" */

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

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

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

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

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

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

    exit(EXIT_SUCCESS);
}