acos(3I)

NAME
     ACOS, DACOS, QACOS, ACOSD, DACOSD, QACOSD - Computes arc cosine
     (inverse cosine)

SYNOPSIS
     ACOS ([X=]x)
     DACOS ([X=]x)
     QACOS ([X=]x)

     ACOSD ([X=]x)
     DACOSD ([X=]x)
     QACOSD ([X=]x)

STANDARDS
     Fortran

     Fortran extensions:  QACOS, ACOSD, DACOSD, QACOSD

DESCRIPTION
     ACOS, DACOS, and QACOS return the arc cosine in radians.  ACOSD,
     DACOSD, and QACOSD return the arc cosine in degrees.  ACOS and ACOSD
     are generic function names; the others are specifics.  These are
     elemental intrinsic functions.  These routines accept the following
     argument:

     x         Must be of type single precision, double precision, or quad
               precision.  The type and kind type of x is identical to the
               type and kind type of the return value.  The absolute value
               of the arguments for ACOS, DACOS, QACOS, ACOSD, DACOSD, and
               QACOSD must be <= 1.  See the RETURN VALUES section for
               information on input data types and return values.

               The terms single precision, double precision, and quad
               precision differ depending on your platform.  For
               platform-specific information, see the TERMINOLOGY section
               of the INTRO_INTRIN(3I) man page.

     For ACOS, DACOS, and QACOS, the result is in radians and is in the
     range 0 <= result <= pi.  The generic form, ACOS, can be used for all
     real data types because it derives its type and kind type from that of
     its argument.

     For ACOSD, DACOSD, and QACOSD, the result is in degrees and is in the
     range 0 <= result <= 180.  The generic form, ACOSD, can be used for
     all real data types because it derives its type and kind type from
     that of its argument.

     A vector version of the single-precision and double-precision ACOS
     intrinsic exists on IRIX systems and is used when -O3 is specified on
     the compiler command line.

     These functions evaluate y = arccos(x).

NOTES
     The ACOS and DACOS intrinsic function names can be passed as
     arguments; the others cannot.

RETURN VALUES
     ACOS and ACOSD return the real arc cosine of their real arguments.

     DACOS and DACOSD return the double-precision arc cosine of their
     double-precision arguments.

     QACOS and QACOSD return the quad-precision arc cosine of their
     quad-precision arguments.

SEE ALSO
     intro_intrin(3I)