catan, catanf, catanl - complex arc tangents
Math library (
libm,
-lm)
#include <complex.h>
double complex catan(double complex z);
float complex catanf(float complex z);
long double complex catanl(long double complex z);
These functions calculate the complex arc tangent of
z. If
y = catan(z), then
z = ctan(y). The
real part of y is chosen in the interval [-pi/2,pi/2].
One has:
catan(z) = (clog(1 + i * z) - clog(1 - i * z)) / (2 * i)
These functions were added in glibc 2.1.
For an explanation of the terms used in this section, see
attributes(7).
Interface |
Attribute |
Value |
catan (), catanf (), catanl () |
Thread safety |
MT-Safe |
C99, POSIX.1-2001, POSIX.1-2008.
/* 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 = catan(z);
printf("catan() = %6.3f %6.3f*i\n", creal(c), cimag(c));
f = (clog(1 + i * z) - clog(1 - i * z)) / (2 * i);
printf("formula = %6.3f %6.3f*i\n", creal(f), cimag(f));
exit(EXIT_SUCCESS);
}
ccos(3),
clog(3),
ctan(3),
complex(7)