cacos3
Complex arc cosine
Usage
#include <complex.h>
double complex cacos(double complex z); float complex cacosf(float complex z); long double complex cacosl(long double complex z);
Library
Math library (libm, -lm)
Overview
These functions calculate the complex arc cosine of z. If y = cacos(z), then z = ccos(y). The real part of y is chosen in the interval [0,pi].
One has:
cacos(z) = -i * clog(z + i * csqrt(1 - z * z))
Attributes
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
| cacos(), cacosf(), cacosl() | Thread safety | MT-Safe |
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;
double complex i = I;
if (argc != 3) {
fprintf(stderr, "Usage: %s <real> <imag>\n", argv[0]);
exit(EXIT_FAILURE);
}
z = atof(argv[1]) + atof(argv[2]) * I;
c = cacos(z);
printf("cacos() = %6.3f %6.3f*i\n", creal(c), cimag(c));
f = -i * clog(z + i * csqrt(1 - z * z));
printf("formula = %6.3f %6.3f*i\n", creal(f), cimag(f));
exit(EXIT_SUCCESS);
}
Releases
12 releases since Debian 3.1 (Sarge); the text changed 11 times.