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In mathematics, and particularly in formal algebra, an indeterminate is a symbol that is treated as a variable, but does not stand for anything else but itself and is used as a placeholder in objects such as polynomials and formal power series. In particular it does not designate a constant or a parameter of the problem, it is not an unknown that could be solved for, and it is not a variable designating a function argument or being summed or integrated over; it is not any type of bound variable. ==Polynomials== A polynomial in an indeterminate ''X'' is an expression of the form , where the ''a''''i'' are called the coefficients of the polynomial. Two such polynomials are equal only if the corresponding coefficients are equal.〔Herstein, Section 3.9〕 In contrast, two polynomial functions in a variable ''x'' may be equal or not depending on the value of ''x''. For example, the functions : are equal when ''x''=3 and not equal otherwise. But the two polynomials : are unequal since 2 does not equal 5 and 3 does not equal 2. In fact :, does not hold ''unless'' ''a'' = 2 and ''b'' = 3. This is because ''X'' is not, and does not designate, a number. The distinction is subtle since a polynomial in ''X'' can be changed to a function in ''x'' by substitution. But the distinction is important because information may be lost when this substitution is made. Working in modulo 2: : so the polynomial function ''x''−''x''2 is identically equal to 0 for ''x'' having any value in the modulo 2 system. But the polynomial ''X''-''X''2 is not the zero polynomial since the coefficients, 0, 1 and −1, are not all zero. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Indeterminate (variable)」の詳細全文を読む スポンサード リンク
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