CentOS 5.6

GNU/Linux	CentOS 5.6
	catanf(3)

CATAN

NAME

catan, catanf, catanl − complex arc tangents

#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.

The catan() function calculates the complex atan(). 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) = 1/2i clog((1+iz)/(1−iz)).

C99