数列是一类特殊的函数,其定义域只能取正整数集(或其子集).牵涉到数列的单调性问题,或求与数列最大(小)项的问题,往往需要从函数角度去分析判断数列的特性,通过对函数定义域限定为正整数集范围内,利用函数的单调性或函数的值域来寻求.本文就数列这一特殊函数,例析在涉及到单调性问题时的一般 The sequence is a special kind of function whose domain can only take the set of positive integers (or its subsets). The problems involving the monotonicity of the sequence or the problem of finding the largest (small) term of the sequence often need to be analyzed from a functional point of view Judging the characteristics of the sequence, the function domain is defined as a set of positive integers by using the monotonicity of the function or the range of the function to seek.In this paper, the special function of the sequence is analyzed in the case of monotonicity