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
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)
VERSIONS
These functions first appeared in glibc in version 2.1.
ATTRIBUTES
For an explanation of the terms used in this section, see
attributes(7).
Interface Attribute Value
catan(), catanf(), catanl() Thread safety MT-Safe
CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.
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 ALSO
ccos(3), clog(3), ctan(3), complex(7)
COLOPHON
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description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
2015-04-19 CATAN(3)
Free and Open Source Software