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);

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

clog(3), ccos(3)