任何一种解题方法都要以某种思维形式为背景,思考问题的角度对问题的解答有直接影响.一个问题,从正面思考不易或无法求得解答时,反面思考便成为一种合理的思考方式.所谓反面思考,就是从问题的反面入手,先考察结果的对立面或假定需证的结论不成立,看能推演出什么结果,从而解决问题. Any problem-solving method must be based on a certain form of thinking. The perspective of thinking has a direct impact on the solution of a problem. When a problem is considered difficult or impossible to obtain from a positive thinking, negative thinking becomes a reasonable one. The way of thinking. The so-called negative thinking is to start from the opposite side of the question. The opposite of the first examination result or the conclusion of the hypothetical evidence need not be established, and what results can be deducted to solve the problem.