cacos, cacosf, cacosl − complex arc cosine
Math library (libm, −lm)
#include <complex.h>
double
complex cacos(double complex z);
float complex cacosf(float complex z);
long double complex cacosl(long double complex
z);
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))
For an explanation of the terms used in this section, see attributes(7). |
C11, POSIX.1-2008.
glibc 2.1. C99, POSIX.1-2001.
/* 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);
}
ccos(3), clog(3), complex(7)