x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
catan(3) Library Functions Manual catan(3)
NAME
catan, catanf, catanl - complex arc tangents
LIBRARY
Math library (libm, -lm)
SYNOPSIS
#include <complex.h>
double complex catan(double complex z);
float complex catanf(float complex z);
long double complex catanl(long double complex z);
DESCRIPTION
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)
ATTRIBUTES
For an explanation of the terms used in this section, see at-
tributes(7).
+--------------------------------------------+---------------+---------+
|Interface | Attribute | Value |
+--------------------------------------------+---------------+---------+
|catan(), catanf(), catanl() | Thread safety | MT-Safe |
+--------------------------------------------+---------------+---------+
STANDARDS
C11, POSIX.1-2008.
HISTORY
glibc 2.1. C99, POSIX.1-2001.
EXAMPLES
/* 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);
}
SEE ALSO
ccos(3), clog(3), ctan(3), complex(7)
Linux man-pages 6.04 2023-03-30 catan(3)
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