VMS Help FORTRAN, Intrinsic Procedures, ACOSD  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  ACOSD (real-number)

  A function that returns the arc cosine of the argument in degrees.
  The value of the argument must be between 0 (exclusive) and 1
  (inclusive).

  +------+---------+----------+------------+-------------+
  | Args | Generic | Specific |  Argument  | Result Type |
  +------+---------+----------+------------+-------------+
  |  1   |  ACOSD  |  ACOSD   | REAL*4     | REAL*4      |
  |      |         |  DACOSD  | REAL*8     | REAL*8      |
  |      |         |  QACOSD  | REAL*16    | REAL*16     |
  +------+---------+----------+------------+-------------+