Cacosh (3) Linux Manual Page

NAME

cacosh, cacoshf, cacoshl – complex arc hyperbolic cosine

SYNOPSIS

#include <complex.h>

double complex cacosh(double complex z);
float complex cacoshf(float complex z);
long double complex cacoshl(long double complex z);

Link with -lm.

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))

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`
`cacosh`(), `cacoshf`(), `cacoshl`()	Thread safety	MT-Safe

CONFORMING TO

C99, POSIX.1-2001, POSIX.1-2008.

EXAMPLES

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

f = 2 * clog(csqrt((z + 1)/2) + csqrt((z – 1)/2));
printf("formula = %6.3f %6.3f*i
", creal(f2), cimag(f2));

exit(EXIT_SUCCESS); }

COLOPHON

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cacosh (3) Linux Manual Page