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读了《江西教育》1983年第10期《二次函数最大值应用题与等周问题》一文,颇受启发。该文运用等周问题的初步知识,来解答某些二次函数最大值应用题,构思巧妙,解法简便。但其中例2的解法,似可作进一步地研究;例5的解法,似有疏忽之处;且关于这方面的教学建议,也值得商榷。对此作如下陈述:一、原文例2中的矩形窗框,中间档料的根数为2(如图1)。原文巧妙地利用了这一特点,将原窗框作“等效变形”,变为两个周长相等且为定值的小
He was inspired by the article “Electrical Education in Jiangxi,” Issue 10, 1983, “The Problem of Quadratic Function Maximization Problem and Equivalence Problem.” This article uses the preliminary knowledge of the isoperimetric problem to solve some of the quadratic function maximum application problems, the concept is ingenious, and the solution is simple. However, the solution to Case 2 seems to be available for further study; the solution to Case 5 seems to be negligent; and the teaching suggestions in this area are also worth discussing. This is stated as follows: 1. The rectangular window frame in the original text example 2 has a root number of 2 (Figure 1). The original text cleverly used this feature to make the original window frame “equivalent deformation” into two small and constant perimeters.