本文举例介绍“进退互化”的解题策略.所谓进,就是把所求的数学问题推进到一般情形下进行研究,所谓退,就是在求解一个一般问题时,先对它作特殊化处理,以期找到解题的方向和解题途径.解题中有时要以退求进,有时要先进后退.恰当运用进退的互化是解决数学问题的一条重要策略.下面举几例 This article gives an example to introduce the problem-solving strategy of “advancing and retorting each other.” The so-called advancing is to push the mathematical problem sought into the general situation for research. The so-called retreat means that when solving a general problem, Processing, in order to find the direction of the problem-solving and problem-solving approach. Sometimes solve the problem to withdraw from the progress, and sometimes to advanced back. Appropriate use of advance and retreat of each other is an important strategy to solve mathematical problems.