CACOS(3) Linux Programmer's Manual CACOS(3)
NAME
cacos, cacosf, cacosl - complex arc cosine
SYNOPSIS
#include <complex.h>
double complex cacos(double complex z);
float complex cacosf(float complex z);
long double complex cacosl(long double complex z);
Link with -lm.
DESCRIPTION
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))
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 |
+-----------------------------+---------------+---------+
|cacos(), cacosf(), cacosl() | Thread safety | MT-Safe |
+-----------------------------+---------------+---------+
CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.
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;
double complex i = I;
if (argc != 3) {
fprintf(stderr, "Usage: %s <real> <imag>
", argv[0]);
exit(EXIT_FAILURE);
}
z = atof(argv[1]) + atof(argv[2]) * I;
c = cacos(z);
printf("cacos() = %6.3f %6.3f*i
", creal(c), cimag(c));
f = -i * clog(z + i * csqrt(1 - z * z));
printf("formula = %6.3f %6.3f*i
", creal(f), cimag(f));
exit(EXIT_SUCCESS);
}
SEE ALSO
ccos(3), clog(3), complex(7)
COLOPHON
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latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.
2015-04-19 CACOS(3)
