cacoshf

(3)

complex arc hyperbolic cosine

Library functionsmanpages-dev 6.9.1-1also documents cacosh, cacoshl

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

LIBRARY

Math library (libm, -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))

ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).

Interface	Attribute	Value
cacosh (), cacoshf (), cacoshl ()	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>\n", argv[0]);


        exit(EXIT_FAILURE);


    }


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


    c = cacosh(z);


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


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


    printf("formula  = %6.3f %6.3f*i\n", creal(f), cimag(f));


    exit(EXIT_SUCCESS);
}