CATAN(3) Linux Programmer's Manual CATAN(3)NAME
catan, catanf, catanl - complex arc tangents
SYNOPSIS
#include <complex.h>
double complex catan(double complex z);
float complex catanf(float complex z);
long double complex catanl(long double complex z);
Link with -lm.
DESCRIPTION
The catan() function calculates 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)
VERSIONS
These functions first appeared in glibc in version 2.1.
CONFORMING TO
C99.
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>\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(f2), cimag(f2));
exit(EXIT_SUCCESS);
}
SEE ALSOccos(3), clog(3), ctan(3), complex(7)COLOPHON
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description of the project, and information about reporting bugs, can
be found at http://man7.org/linux/man-pages/.
2011-09-15 CATAN(3)
