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1.(安徽卷,文7)图1中的图象所表示的函数的解析式为( ).A.y=3/2|x-1|(0≤x≤2)B.y=3/2-3/2|x-1|(0≤x≤2)c.y=3/2-|x-1|(0≤x≤2)D.y=1-|x-1|(0≤x≤2)解答途径:将点(1,3/2)与(2,0)代入,选项 A、选项 C、选项 D 均不适合,选项 B 适合.故选 B.解题感悟:用特殊点法解答此题不失为一种好的方法.教学中应强化符号语言、图形语言、文字语言之间的相互转换.本题就是一个图形转换成符号的问题。2.(江苏卷,9)已知二次函数 f(x)=ax~2+bx+c的导数为 f′(x),f′(0)>0,对于任意实数 x,有 f(x)≥0,则 f(1)/f′(0)的最小值为( ).A.3 B.5/2 C.2 D.3/2
1. (Anhui volume, text 7) The analytical expression of the function represented by the image in Fig. 1 is (). Ay=3/2|x-1|(0≤x≤2) By=3/2-3 /2|x-1|(0≤x≤2)cy=3/2-|x-1|(0≤x≤2) Dy=1-|x-1|(0≤x≤2) Solution : Substituting points (1, 3/2) and (2, 0), Option A, Option C, and Option D are not suitable, Option B is appropriate. Therefore, B. Problem Solving: Using special points to answer this question is A good method. Teaching should strengthen the mutual conversion between symbolic language, graphic language, and textual language. This question is a problem of graphic conversion into symbols. 2. (Jiangsu Volume, 9) The derivative of the known quadratic function f(x)=ax~2+bx+c is f’(x), f’(0)> 0, for any real number x, there is f ( x) ≥ 0, then the minimum value of f(1)/f’(0) is (). A.3 B.5/2 C.2 D.3/2