1

3若3a4，則log2的值等于 3 B.

D. y2x2x2

y

3yx

ylog12y3(1xy33311

3

x的圖象 0x32x50在區(qū)間[2,3x2.50個(gè)有根區(qū)間是

[2

,4

4函數(shù)f(x)logx與f(x)4x的圖象 4關(guān)于x軸對(duì) B.關(guān)于y軸對(duì)C.關(guān)于原點(diǎn)對(duì) D.關(guān)于直線y＝x對(duì)1h50km/hAAx（km）t xx60t (0tx50t25,(tx

(0t(2.5t(3.5t定義域?yàn)镽的奇函數(shù)f(x)是減函數(shù)，當(dāng)不等式f(a)f(a2)0成立時(shí)，實(shí)數(shù)a的取 B.1aC.a0或a y1x)0

1的定義域1 x2 (xf(x

，若f(a)2，則實(shí)數(shù) x2()2

(x定義域?yàn)镽f(xx1x2f(x1x2f(x)的解析式可以 （寫出一個(gè)符合條件的函數(shù)即可

f(x1f(x2偶函數(shù)f(x)在(,0)內(nèi)是減函數(shù)，試比較f(2)與f(3)的大小關(guān) 已知集合Ax|log2x2BaAB則實(shí)數(shù)a的取值范圍是(c,)，那么，其中 已知全集URA{x|1x3Bx|x23x20（1）AB（2）求(CUABf(xx22xg(x1f(x1xg(xg(xf(x4x1xyf(x4f(x在區(qū)間1,2 2 f(x)logx3)(x24x3)f(xf(x)1f(x)x22ax3在區(qū)間[0,1]g(ap(a)g(ap(af(x32a1. 2. 5. 6. 5.f(xx32x5f(210f(3160f(2.55.6250，故下一個(gè)有根區(qū)間是[2,2.5]。8.f(af(a20

f(a2f(af(xf(a2

f(a)f(xRa2a，解得a1a09.{x|x1且x

11.4f(x)0f(x)2x

f(2)f

14.f(xf(2)f(2f(x在(,0f(3)f(2

f(2)log2x2,x4a4，又a的取值范圍為(c,，c4（1）x23x20，得(x2)(x1)0x2x1AB{x|1x3}{x|x2,或x1{x|1x1或2x3}（2）CUAx|x1,或x3(CUABx|x1,或x3{x|x2,或x{x|x2,或x1}（1）f(x)x22xf(x1)x21g(x)

1f(x1)x

x2。x（2）g(x(x)2

證明：g(x) 1

g(x)g(x1（1）f(x44x

4f(x40，得4xx

40x即4x24x10x12yf(x412（2）x1，x2是區(qū)間(1,xx21f(x1fx24x11

(4x2

1)4(x1x21

14x1x214，

x1x22x1x24

xxx1x2

0，所以

x2

1

40f(x1fx2，1

f(x在區(qū)間2

,x24x3根據(jù)對(duì)數(shù)定義，知x3x3

x3或x即xx( ( (不等式 (x24x3)1 (x2( ( (x3x2

0x34x3x3或x24x3xx24x3

3x2，或0x1，或3x（1）f(x)(xa)23a2a1g(a)2a1g(a)2

ff

maxmax

f(1)42af(0)34g(a)

(a21

(a a0p(a

f(x)min

f(0)當(dāng)0a1時(shí)，p(a)f 3a2a1p(a

f(x)min

p(a3a2,

(a(0a(a（2）1a1g(a)