解题时,依据题中的结论与条件的关系,恰当地构造一个辅助函数,把结论转化为研究这一函数的性质,由此达到解题的目的,这种方法叫做辅助函数法。下面介绍几种常见的辅助函数构造法,供参考。一、直接法这种方法就是在仔细审题的基础上,直接运用题目的条件或结论构造一辅助函数,使所求问题发生转化。直接法是一种常用的 When solving a problem, based on the relationship between the conclusions and conditions in the problem, an auxiliary function is properly constructed, and the conclusion is converted into a study of the nature of the function, thereby achieving the purpose of solving the problem. This method is called the auxiliary function method. The following introduces several common auxiliary function construction methods for reference. First, the direct method This method is based on a careful examination of the problem, the direct use of the conditions or conclusions of the problem to construct an auxiliary function, so that the problem is transformed. Direct method is a commonly used