题目
题型:单选题难度:简单来源:不详
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A.0<x1x2<1 | B.x1x2=1 | C.1<x1x2<2 | D.x1x2≥2 |
答案
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分别画出左右两边函数的图象,如图所示.
由指数与对数函数的图象知:x1>1>x2>0,
于是有lo
g | x12 |
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g | x2
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故选A.
核心考点
试题【设函数f1(x)=log2x-(12)x,f2(x)=log12x-(12)x的零点分别为x1,x2,则( )A.0<x1x2<1B.x1x2=1C.1<x1】;主要考察你对对数函数的性质等知识点的理解。[详细]
举一反三
题型:(a>0,a≠1),若x1<x2<x3<x4,且f(x1)=f(x2)=f(x3)=f(x4),则
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A.2 | B.4 | C.8 | D.随a值变化 |
A.①② | B.②③ | C.①③ | D.③④ |
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(1)求它的定义域,值域;
(2)判定它的奇偶性和周期性;
(3)判定它的单调区间及每一区间上的单调性.