数列的通项有时是由递推公式给出的,如何由数列的递推公式求通项呢?同学们熟悉的是等差数列和等比数列,所以首先要看从已知的递推公式经过转化是否可以化为等差数列或等比数列.对于不能转化为等差数列或等比数列形式的题目,则要细心分析.寻找规律以正确求解. The general term of the series is sometimes given by a recurrence formula. How do we find the general term from the recurrence formula of the series? The students are familiar with the arithmetic progression and the geometric progression, so the first step is to look at the known recursion formula. After transformation, whether it can be converted into arithmetic progression or geometric progression. For problems that cannot be converted to arithmetic progression or geometric progression, it is necessary to analyze carefully. Find the law to solve it correctly.