SLATEC Routines --- DACOSH ---

*DECK DACOSH
      DOUBLE PRECISION FUNCTION DACOSH (X)
C***BEGIN PROLOGUE  DACOSH
C***PURPOSE  Compute the arc hyperbolic cosine.
C***LIBRARY   SLATEC (FNLIB)
C***CATEGORY  C4C
C***TYPE      DOUBLE PRECISION (ACOSH-S, DACOSH-D, CACOSH-C)
C***KEYWORDS  ACOSH, ARC HYPERBOLIC COSINE, ELEMENTARY FUNCTIONS, FNLIB,
C             INVERSE HYPERBOLIC COSINE
C***AUTHOR  Fullerton, W., (LANL)
C***DESCRIPTION
C
C DACOSH(X) calculates the double precision arc hyperbolic cosine for
C double precision argument X.  The result is returned on the
C positive branch.
C
C***REFERENCES  (NONE)
C***ROUTINES CALLED  D1MACH, XERMSG
C***REVISION HISTORY  (YYMMDD)
C   770601  DATE WRITTEN
C   890531  Changed all specific intrinsics to generic.  (WRB)
C   890531  REVISION DATE from Version 3.2
C   891214  Prologue converted to Version 4.0 format.  (BAB)
C   900315  CALLs to XERROR changed to CALLs to XERMSG.  (THJ)
C***END PROLOGUE  DACOSH