DragonFly On-Line Manual Pages

CATAN(3)              DragonFly Library Functions Manual              CATAN(3)

NAME
     catan, catanf, catanl -- complex circular arc tangent

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
     The catan(), catanf() and catanl() functions compute the complex circular
     arc tangent of z.

     If z = x + iy, then

           Re catan(z) = 1/2 * atan(2x / (1 - x^2 - y^2)) + k Pi.
           Im catan(z) = 1/4 * log((x^2 + (y + 1)^2) / (x^2 + (y - 1)^2)).

RETURN VALUES
     The catan(), catanf() and catanl() functions return the complex circular
     arc tangent of z with unbounded imaginary part, and real part in the
     interval [-Pi/2, Pi/2].

SEE ALSO
     cacos(3), casin(3)

STANDARDS
     The catan(), catanf() and catanl() functions conform to ISO/IEC 9899:1999
     (``ISO C99'').

DragonFly 4.1                    June 5, 2013                    DragonFly 4.1