cacosh(3) Linux Man Page - System Grab Bag

Name

cacosh, cacoshf, cacoshl - complex arc hyperbolic cosine

Library

Math library ( libm ", " -lm )

Synopsis

#include <complex.h> 
double complex cacosh(double complex  z );
float complex cacoshf(float complex  z );
long double complex cacoshl(long double complex  z );

Description

These functions calculate the complex arc hyperbolic cosine of z. If y\ =\ cacosh(z), then z\ =\ ccosh(y). The imaginary part of y is chosen in the interval [-pi,pi]. The real part of y is chosen nonnegative.

One has:

    cacosh(z) = 2 * clog(csqrt((z + 1) / 2) + csqrt((z - 1) / 2))

Attributes

For an explanation of the terms used in this section, see attributes(7). allbox; lbx lb lb T{ cacosh()cacoshf()cacoshl()

Interface	Attribute	Value
T}	Thread safety	MT-Safe

Standards

C11, POSIX.1-2008.

History

C99, POSIX.1-2001. glibc 2.1.

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

    f = 2 * clog(csqrt((z + 1)/2) + csqrt((z - 1)/2));
    printf("formula  = %6.3f %6.3f*i\en", creal(f), cimag(f));

    exit(EXIT_SUCCESS);
}