catan, catanf, catanl – complex arc tangents

USAGE
       #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
       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)).

CONFORMING TO
       C99

SEE ALSO
       ccos(3), clog(3), complex(7)