《中学生数学》2006年第11(上)期发表武增明老师的一篇文章《用待定系数法求三角函数最值》,笔者认为该文只是提供了一种行得通的解法,由于拆项技巧太强,又用了高中数学不需要掌握的a+b+c≥3(abc)~(1/3)(a>0,b>0,c>0),故用待定系数法来解决这类问题,学生不易接受.笔者研究发现该文例题若用换元 The mathematics of middle school students published an article by Wu Zengming in the 11th (the first) period of 2006, “Calculating the trigonometric function with undetermined coefficient method”. The author thinks this article only provides a feasible solution because of the demolition technique. Too strong, but also use a + b + c ≥ 3 (abc) ~ (1/3) (a> 0, b> 0, c> 0) that high school mathematics do not need to master, so use undetermined coefficient method to solve this Class problems are not easy for students to accept.