catan (3)
NAME
catan, catanf, catanl - complex arc tangentsSYNOPSIS
#include <complex.h>
double complex catan(double complex z);
float complex catanf(float complex z);
long double complex catanl(long double complex z);
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 ALSO
ccos(3), clog(3), ctan(3), complex(7)COLOPHON
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