VMS Help PASCAL, Predeclared Routines, Arithmetic, COS  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  The COS function returns a real value that represents the cosine
  of the specified parameter.

  Syntax:

     COS( x )

  The parameter 'x' can  be  an  integer  or  REAL  type,  and  is
  expressed in radians.