递推公式是给出数列的一种基本方式,是数列各项间内在关系的本质反映,求出数列通项往往是求解数列综合问题的关键.如何能化陌生为熟知,化抽象为具体,进而解决问题呢?变换转化是解决此问题最重要和最行之有效的策略.所谓变换转化,其实质是合理变换转化递推关系,构造一个新的数列 The recursion formula is a basic way to give out a series of numbers and is the essential reflection of the inner relations among the various series of numbers. It is often the key to solve a series of comprehensive problems when formulating a series of items. How to turn strangers into familiarity and abstraction as concrete, And then solve the problem Transform transformation is the most important and effective strategy to solve this problem.The so-called transformation transformation, its essence is a reasonable transformation transformation transformation, construct a new series