/sys$common/syshlp/helplib.hlb RTL Routines, MTH$, MTH$xATAND2, Arguments  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 sine

    OpenVMS usage:floating_point
    type:         F_floating, D_floating, G_floating
    access:       read only
    mechanism:    by reference
    Dividend. The sine argument is the address of a floating-point
    number that is this dividend. For MTH$ATAND2, sine specifies an
    F-floating number. For MTH$DATAND2, sine specifies a D-floating
    number. For MTH$GATAND2, sine specifies a G-floating number.

 cosine

    OpenVMS usage:floating_point
    type:         F_floating, D_floating, G_floating
    access:       read only
    mechanism:    by reference
    Divisor. The cosine argument is the address of a floating-point
    number that is this divisor. For MTH$ATAND2, cosine specifies an
    F-floating number. For MTH$DATAND2, cosine specifies a D-floating
    number. For MTH$GATAND2, cosine specifies a G-floating number.