对某些数学问题,如果先对其特殊情况进行分析,再加以归纳,往往可以发现解决问题的方法.特殊值法就是根据题设条件取一些特殊值,然后探求出结论或满足结论所需要的条件.本文结合中考题和竞赛题说明特殊值法的应用. For some mathematics problems, if we analyze their special circumstances first and then generalize, we can often find a solution to the problem. The special value method is to take some special values ​​according to the conditions of the problem, and then explore the conclusions or meet the conclusions needed Conditions. This article combines the examination questions and competition questions to illustrate the application of the special value method.