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两只小麻雀与两只黑颈鹤在鸟类学家那里引起的感受可以说是天壤之别,前者普普通通,随处可见,后者珍稀无比,全世界才四千多只。然而,在数学的眼光里,他们没有丝毫的区别,都是“2”。篮球、兵乓球、铅球,虽然材质各异,无非都是球体。同样是数学的眼光,也有高低之分、远近之别,更有“狭”、“恰”、“过”的数学评价。为了看出y=-2x2与y=-2x2+2x-3/2的图像关系,大家都知道需将-2x2+2x-3/2变形为-2(x-1/2)2-1。对变形的目的却可有三种不同的理解,理解一:为了识别顶点坐标;理解二:为了将运算差异整理在首
Two little sparrows and two black-necked cranes in the ornithologist where the feelings caused by it can be said is a world of difference, the former common, everywhere, the latter extremely rare, the world only 4,000 only. However, in the mathematical view, they are not the slightest difference, are “2 ”. Basketball, table tennis, shot put, although the material varies, nothing more than the ball. The same is the mathematical perspective, but also the level of points, far and near the difference, more “narrow ”, “just ”, “over ” mathematical evaluation. In order to see the image relationship between y = -2x2 and y = -2x2 + 2x-3/2, we all know that it is necessary to transform -2x2 + 2x-3/2 into -2 (x-1/2) 2-1. There are three different understandings of the purpose of deformation, one to understand: To identify vertex coordinates; Understanding two: In order to align the differences in the operation