求数列的通项公式,由于没有固定的程式可循,学生一般感到较为困难。下面我们通过一组典型例题提出一套解题方法与常用技巧,以供参考,希望对提高学生分析和解决求数列通项问题的能力有所助益。一、观察法通过观察已知数列的前若干项,摸清各项符号的变化规律,搞清不变的数和不变的运算以及各项可变的数与所在项的项数的关 There is no fixed program to follow for the general formula of the series. Students generally find it more difficult. Below, we propose a set of problem-solving methods and common techniques through a set of typical examples. For reference, we hope to help students improve their ability to analyze and solve problems in the series. First, the observation method, by observing the first few items of the known series, finds out the changing rules of each symbol, finds out the invariant numbers and the constant operations, and the relationship between the variable number and the item number of the item.