在学习导数和微分以前,用初等方法求极值最常见的有观察法、配方法、判别式法、不等式法等。下面首先通过教材(以下均指高中课本)中的几个例题及习题进行分析,说明用初等方法求极值的局限性.进而揭示函数的极值与最值的 Before learning the derivatives and differentiation, the most common methods for finding extremum using the elementary method are observation method, matching method, discriminant method, and inequality method. The following first analyzes several examples and exercises in textbooks (hereafter referred to as high school textbooks) to illustrate the limitations of extremum using elementary methods, and to reveal the extremum and the maximum of the function.