cacos, cacosf, cacosl – complex arc cosine

USAGE
       #include <complex.h>

       double complex cacos(double complex z);
       float complex cacosf(float complex z);
       long double complex cacosl(long double complex z);

       Link with -lm.

DESCRIPTION
       The  cacos()  function calculates the complex acos().  If y = cacos(z),
       then z = ccos(y).  The real part of y is chosen in the interval [0,pi].

       One has cacos(z) = -i clog(z+csqrt(z*z-1)).

CONFORMING TO
       C99

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