有些数学竞赛题,看似困难,无从下手,若利用“夹逼法”,设法将待求目标夹在两个数值之间,使待求目标的取值范围尽可能缩小,就可将问题化难为易,巧妙获解,现举例说明。一、求值 Some math contest questions may seem difficult and they can’t start. If you use the “pinch force method” and try to pinch the goal to be between two values ​​so that the value range of the target to be sought can be reduced as much as possible, problems can be solved. It is hard to understand and cleverly solved. Here is an example. First, the evaluation