数学归纳法是证明与正整数有关的数学命题的一种重要方法,在各类考试中有非常广泛的应用.使用数学归纳法证题一般分两步,即归纳奠基和归纳递推,证题的难点在于归纳递推.归纳递推证明的基本思路是将n=k+1的情形先化归为n=k的情形,然后用归纳假设递进到n=k+1的情形.如果从n=k到n=k+1有确定的递推关系,问题往往比较简单.但在很多情况下,递推关系却并不存在,或递推关系存在,却难以直接使用,此时需要自主构建, Mathematical induction is an important method to prove the mathematical propositions related to positive integers, and it has a very wide range of applications in all kinds of examinations.Using mathematical induction is generally divided into two steps, that is to say, The difficulty of inducing recursion is that the basic idea of ​​inductive recursion is to first classify n = k + 1 into n = k and then use inductive assumptions to proceed to the case of n = k + 1. If There are definite recursion relations between n = k and n = k + 1, and the problems are often simpler, but in many cases, the recursive relationship does not exist or the recursion relationship exists but it is difficult to directly use it. In this case, autonomous Construct,