Whole note they may occasionally be put under a different line (or ledger line) in more complicated polyphonic passages, or when two instruments or vocalists are written on one staff and one is temporarily silent. The whole note and whole rest may also be used in music of free rhythm, such as Anglican chant, to denote a whole measure, irrespective of the time of that measure. The whole rest can be used this way in almost all or all forms of music. The symbol is first found in music notation from the late thirteenth century . The whole note derives from the
Time value of money is to emphasize that "u" is a "parameter" (fixed in any instance—the time when the cash flow will occur), while "t" is a "variable" (time). In other words, future cash flows are exponentially discounted (exp) by the sum (integral, formula_44) of the future discount rates (formula_45 for future, "r"("v") for discount rates), while past cash flows are worth 0 (formula_46), because they have already occurred. Note that the value "at" the moment of a cash flow is not well-defined – there is a discontinuity at that point, and one can use a convention (assume cash flows have already occurred, or