tan(3I)

NAME
     TAN, DTAN, QTAN, TAND, DTAND, QTAND - Computes tangent

SYNOPSIS
     TAN ([X=]x)
     DTAN ([X=]x)
     QTAN ([X=]x)

     TAND ([X=]x)
     DTAND ([X=]x)
     QTAND ([X=]x)

IMPLEMENTATION
     UNICOS, UNICOS/mk, IRIX systems

     CF90, MIPSpro 7 Fortran 90, MIPSpro Fortran 77

STANDARDS
     Fortran

     Fortran extension:  QTAN, TAND, DTAND, QTAND

DESCRIPTION
     These functions evaluate y = tan(x).  They are elemental intrinsic
     functions.  They accept the following argument:

     x         Must be of type real.  For TAN, DTAN, and QTAN, x must be
               specified in radians and is treated as modulo 2 * pi.  For
               TAND, DTAND, and QTAND, x must be specified in degrees and
               is treated as modulo 360.

     TAN and TAND are generic function names; the rest are specifics.

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

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

     On UNICOS and UNICOS/mk systems, the following return values occur:

     * On systems that support the IEEE standard for floating-point
       arithmetic,                 25
       TAN(x) = NaN if |x| > pi * 2

     * On systems that do not support the IEEE standard for floating-point
       arithmetic,               25
       TAN(x) = 0 if |x| > pi * 2

     On IRIX systems, the following return value occurs:
                                      19
          TAN(x) = NaN if |x| > pi * 2

     On all systems that support the IEEE standard for floating-point
     arithmetic, the following is true:

          TAN(NaN) = NaN

RETURN VALUES
     TAN and TAND return the real tangent of their real argument.

     DTAN and DTAND return the double-precision real tangent of their
     double-precision real argument.

     QTAN and QTAND return the quad-precision real tangent of their
     quad-precision real argument.

     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.

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