A. )0(log 12>+=x x y
B. )1)(1(log 2>-=x x y
C. )0(log 12>+-=x x y
D. )1)(1(log 2->+=x x y 5.设32log ,log log a b c π===
A. a b c >>
B. a c b >>
C. b a c >>
D. b c a >>
6. 2
log 的值为( ) A . B C .12
- D . 1
2
3
7.设函数()y f x =在(,)-∞+∞内有定义,对于给定的正数K ,定义函数
(),(),(),().K f x f x K f x K f x K ≤⎧=⎨
>⎩取函数()2x
f x -=。当K =12时,函数()K f x 的单调递增区间为 ( ) A .(,0)-∞ B .(0,)+∞ C .(,1)-∞- D .(1,)+∞ 8.下列函数()f x 中,满足“对任意1x ,2x ∈(0,+∞),当1x <2x 时,都有
1()f x >2()f x 的是( ) A .()f x =
1
x
B. ()f x =2(1)x - C .()f x =x e D.()ln(1)f x x =+
9.已知函数()f x 满足:x ≥4,则()f x =1
()2
x ;当x <4时()f x =(1)f x +,则
2(2log 3)f +=( ) A.124 B.1
12 C.18 D.38
10.函数)(21R x y x ∈=+的反函数是
A. )0(log 12>+=x x y
B.)1)(1(log 2>-=x x y
C.)0(log 12>+-=x x y
D.)1)(1(log 2->+=x x y
11.设曲线1*()n y x n N +=∈在点(1,1)处的切线与x 轴的交点的横坐标为n x ,则
12n x x x ⋅⋅
⋅的值为( ) A.
1n B.11n + C. 1
n
n + D.1 12.已知函数()f x 的反函数为()()10g x x =+2lgx >,则=+)1()1(g f (A )0 (B )1 (C )2 (D )4
13.若2log a <0,1
()2
b >1,则
( )
A .a >1,b >0
B .a >1,b <0 C. 0<a <1, b >0 D. 0<a <1, b <0
14.已知函数22log (2)()24
(22
a x x f x x x x x +≥⎧⎪
==⎨-<⎪
-⎩当时在点处当时)连续,则常数a 的值是 ( )
4
A.2 B.3 C.4 D.515.若函数()f x 的零点与()422x g x x =+-的零点之差的绝对值不超过0.25, 则()f x 可以是 ( )
A. ()41f x x =-
B. ()2(1)f x x =-
C. ()1x f x e =-
D. ()12f x In x ⎛
⎫=- ⎪⎝
⎭
二、填空题
16.已知集合{}2log 2,(,)A x x B a =≤=-∞,若A B ⊆则实数a 的取值范围是(,)c +∞,其中c = .
17.若函数f(x)=a x -x-a(a>0且a ≠1)有两个零点,则实数a 的取值范围是 . 18.记3()log (1)f x x =+的反函数为1()y f x -=,则方程1()8f x -=的解
x = .
19.
函数2()f x =的定义域为 .
三、解答题
20.已知函数()),0(2R a x x
a
x x f ∈≠+
= (1)判断函数()x f 的奇偶性;
(2)若()x f 在区间[)+∞,2是增函数,求实数a 的取值范围。
5
基本初等函数2
一、选择题
1.已知函数()log (21)(01)x a f x b a a =+->≠,的图象如图所示,则a b ,满足的关系是
A .101a b -<<<
B .
0b D .0a -<2.设⎭⎬⎫⎩
⎨⎧
-∈3,21,1,1α,则使函数αx y =的定义域为R 且为奇函数的所有α的值为
( ) A .1,3
B .-1,1
C .-1,3
D .-1,1,3
3.函数1()x y e x R +=∈的反函数是
( )
A .1ln (0)y x x =+>
B .1ln (0)y x x =->
C .1ln (0)y x x =-->
D .1ln (0)y x x =-+> 4.设2()lg 2x f x x +=-,则2
()()2x f f x
+的定义域为 ( )
x