# cacos.f

          COMPLEX FUNCTION CACOS (Z)
    C***BEGIN PROLOGUE  CACOS
    C***PURPOSE  Compute the complex arc cosine.
    C***LIBRARY   SLATEC (FNLIB)
    C***CATEGORY  C4A
    C***TYPE      COMPLEX (CACOS-C)
    C***KEYWORDS  ARC COSINE, ELEMENTARY FUNCTIONS, FNLIB, TRIGONOMETRIC
    C***AUTHOR  Fullerton, W., (LANL)
    C***DESCRIPTION
    C
    C CACOS(Z) calculates the complex trigonometric arc cosine of Z.
    C The result is in units of radians, and the real part is in the
    C first or second quadrant.
    C
    C***REFERENCES  (NONE)
    C***ROUTINES CALLED  CASIN
    C***REVISION HISTORY  (YYMMDD)
    C   770401  DATE WRITTEN
    C   861211  REVISION DATE from Version 3.2
    C   891214  Prologue converted to Version 4.0 format.  (BAB)
    C***END PROLOGUE  CACOS