Name
catan, catanf, catanl - complex arc tangentsLibrary
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 ofz
. 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 attributes(7).Interface | Attribute | Value |
T} | 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>\en", argv[0]); exit(EXIT_FAILURE); } z = atof(argv[1]) + atof(argv[2]) * I; c = catan(z); printf("catan() = %6.3f %6.3f*i\en", creal(c), cimag(c)); f = (clog(1 + i * z) - clog(1 - i * z)) / (2 * i); printf("formula = %6.3f %6.3f*i\en", creal(f), cimag(f)); exit(EXIT_SUCCESS); }