CACOSH(3) Linux Programmer's Manual CACOSH(3)
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
The cacosh() function calculates the complex arc hyperpolic 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.
CONFORMING TO
C99.
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>
", 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);
}
SEE ALSO
acosh(3), cabs(3), ccosh(3), cimag(3), complex(7)
COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
2011-09-15 CACOSH(3)
