man:catanl
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
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).
allbox; lbw27 lb lb l l l. Interface Attribute Value T{ catan(), catanf(), catanl() T} 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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2015-04-19 CATAN(3)
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