#include <complex.h> double complex cacos(double complex z); float complex cacosf(float complex z); long double complex cacosl(long double complex z);
One has:
cacos(z) = -i * clog(z + i * csqrt(1 - z * z))
| Interface | Attribute | Value |
| cacos(), cacosf(), cacosl() | Thread safety | MT-Safe |
#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));