极值法就是运用极限思维,使某些量的变化抽象成无限大或无限小去思考解决实际问题的一种解题方法。在初中物理解题过程中,有些题用一般的方法解比较繁琐,而用极值法常常能收到立竿见影、豁然开朗的效果。一、判断杠杆的状态 Extreme value method is to use the limit of thinking, so that some changes in the abstraction into infinite or infinitesimal to think about solving a practical problem solving method. In junior high school physics problem-solving process, some problems with the general method of solving more complicated, but with extreme value method can often receive immediate, suddenly results. First, determine the status of the lever