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读了《中小学数学》初中版2013年第1—2期王伟民老师的《确定函数单调性须慎选区间的端点》一文后,笔者对王老师文中的观点及提法有不同意见.现将自己的一些浅显看法写出来,与王老师共同研究.1.文中就一点讨论函数增减性是错误的.根据函数单调性可知:函数的增减性是对函数定义域内的某个区间而言的,是函数在区间上的整体性质,它是一个局部概念,而不是就某一点来说.而文中例1就函数y=x~2-5x+4的顶点(5/2,-9/4)讨论增减性、例2就函数y=-0.1x~2+2.6x+43(0≤x≤30)的三个“特殊点”——边界点(文中称端点)及顶点讨论增
Read “primary and middle school mathematics” junior high school version in 2013 1-2 Wang Weimin teacher “to determine the monotonous function must be carefully selected end of the range of” article, the author of Wang’s views and suggestions have different views. Some of his own shallow view written, and Wang study together.1 The article discussed the function of addition and subtraction is wrong.According to the monotonicity of the function we can see: the function of the addition and subtraction is a function of the region within a certain range , Is the global property of the function in the interval, it is a local concept, not at a certain point. In the first case, the vertices of the function y = x ~ 2-5x + 4 (5/2, -9 / 4) to discuss the addition and subtraction, Example 2 for the function y = -0.1x ~ 2 + 2.6x +43 (0≤x≤30) of the three “special point ” - the boundary point Discussion increased