asin(3I)

NAME
     ASIN, DASIN, QASIN, ASIND, DASIND, QASIND - Computes arc sine (inverse
     sine)

SYNOPSIS
     ASIN ([X=]x)
     DASIN ([X=]x)
     QASIN ([X=]x)

     ASIND ([X=]x)
     DASIND ([X=]x)
     QASIND ([X=]x)

IMPLEMENTATION
     UNICOS, UNICOS/mk, IRIX systems

     CF90, MIPSpro 7 Fortran 90, MIPSpro Fortran 77

STANDARDS
     Fortran

     Fortran extensions:  QASIN, ASIND, DASIND, QASIND

DESCRIPTION
     ASIN, DASIN, and QASIN return the arc sine in radians.  ASIND, DASIND,
     and QASIND return the arc sine in degrees.

     ASIN and ASIND are generic function names; the others are specifics.
     These are elemental intrinsic functions.  They accept the following
     argument:

     x         Must be type real.  The type and kind type of x is identical
               to the type and kind type of the return value.  The absolute
               value of x must be <= 1.  See the RETURN VALUES section for
               information on input data types and return values.

     Vector versions of these intrinsics exist on some systems.  Vector
     versions of ASIN and DASIN exist on UNICOS and UNICOS/mk systems.  On
     UNICOS/mk systems, the vector versions of these intrinsics are used
     when -O vector3 or -O3 have been specified on the compiler command
     line.  On UNICOS/mk systems, the 64-bit intrinsic vectorizes; the
     32-bit version does not.  A vector version of the single-precision and
     double-precision ASIN intrinsic exists on IRIX systems and is used
     when -O3 is specified on the compiler command line.

     These functions evaluate y = arcsin(x).

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

     On CRAY T90 systems that support IEEE arithmetic, the following return
     values occur:

          ASIN(x) = NaN if |x| > 1.0 or x = NaN

RETURN VALUES
     The data type and kind type for single precision, double-precision,
     and quad-precision values differ depending on your platform.  For
     platform-specific information, see the TERMINOLOGY section of the
     INTRO_INTRIN(3I) man page.

     For ASIN, DASIN, and QASIN, the result is in radians and is in the
     range -pi/2 <= result <= pi/2.  For ASIND, DASIND, and QASIND, the
     result is in degrees and is in the range -90 <= result <= 90.

     ASIN and ASIND return the real arc sine of their real arguments.

     DASIN and DASIND return the double-precision arc sine of their
     double-precision arguments.

     QASIN and QASIND return the quad-precision arc sine of their
     quad-precision arguments.

SEE ALSO
     Intrinsic Procedures Reference Manual for the printed version of this
     man page.