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2..2函数的定义域和值域.pdf

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1、1/9 本资料来源于七彩教育网http:/ 22 函数的定义域与值域【知识网络】1函数的定义域；2函数的值域【典型例题】例11）函数)13lg(13)(2xxxxf的定义域是 C）A，31）B(31，31）C(31，1）D(31，）提示：由10310 xx解得113x答案为 C.A|1x xB|2x xC|12x xx且D|12x xx或提示：11()1()111ff xf xx，11101xx，解得12xx且，答案为 C3）函数268ykxxk的定义域为 R，则k的取值范围是 B）A.09kk或 B.1k C.91k D.01k提示：2680kxxk恒成立，0k显然不符，0364(8)0kk

2、 k，解得：1k，选 B.12)yxxx；2232xyx；914xyx；xxycottan5）若的最大值是则yxyx43,122_5_ 提示：设cos,sinxy，则343cos4sin5sinxy（），其最大值为5例21）求下列函数的定义域：xxxxxxf02)1(65)(的定义域2）已知函数()f x的定义域是(,)a b，求函数()(31)(31)F xfxfx的定义域解：由函数解读式有意义，得2/9 0010652xxxxx321011230 xxxxxxx或或或故函数的定义域是),32,1()1,0(2）由113133311133abxaxbaxbabx 函数的定义域不可能为空集，必

3、有1133ab，即2ba此时，1133abx，函数的定义域为 3131 ba，）；例3求下列函数的值域：1）2432yxx；2）12yxx；3）221223xxyxx；4）35yxx；解：1）24(1)4yx，20(1)44x，20(1)42x224(1)44x所给函数的值域为 2，4，则x=212t212tyt21(1)12t，当1t时，max1y所给函数的值域为(,1.3）由已知得：2(21)(21)(31)0yxyxy*）当210y时，12y，代入*）式，不成立，12y当210y时，则：211312231102(21)4(21)(31)0102yyyyyyy 所给函数的值域为31,)10

4、24）530503xxx得由函数定义域为 3,5 2222(3)(5)22 1(4)yxxx又当4x时，2max4y，当35x或时，2min2y224y0y22y文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K

5、8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R

6、4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E

7、1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10

8、Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9

9、U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5

10、Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q10文档编码:CH8K8J7A2R4 HB9E1E1I10Q2 ZU9U4V5F5Q103/9

11、所给2,2函数的值域为例 4已知函数2()3yf xxax在区间 1，1 上的最小值为3，求实数a的值解：43)2()(22aaxxfy1）min12(1)432aayfa当，即时，解得：7a2）当112a，即22a时，2mi n()3324aayf，解得2 6a舍去）3）当12a，即2a时，min(1)43yfa，解得：7a综合1）2）3）可得：a=7【课内练习】1函数23)(xxxf的定义域为 B）A0，错误!B0，3 C3，0 D0，3）zwj2px3C3L 提示：由230 xx得：03x，答案为 B2函数251xyx的值域为 A5|2y y B|0y y C|25y yy且 D2|

12、5y y提示：y)15(5252x,)15(52x 0,y52答案为 D3若函数()f x的定义域为,ab，且0ba，则函数()()()g xf xfx的定义域是 D）A,ab B,ba C,bb D,aa提示：由(0)axbbaaxb得：(0)axbbabxa即axa，答案为D4函数2211xyx的值域为的值域是2,)提示：24(1)923(1)26(1)32(1)xyxxx，文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W

13、3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6

14、ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7

15、X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6

16、文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:C

17、S3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K

18、7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6

19、HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M64/9 当且仅当123(1)32(1)xxx即12x时取等号又函数无最大值，故函数值域为2,)7若一系列函数的解读式相同、值域相同,但其定义域不同,则称这些函数为“同族函数”,那么函数解读式为2yx、值域为 1,4 的“同族函数”共有 9 个.zwj2px3C3L 提示：设函数2yx的定义域为 D，其值域为 1,4，D的所有情形的个数，即是同族函数的个数，D的所有情形为：1,2,1

20、,2,1,2,1,2,1,1,2,1,1,2,1,2,2,1,2,1，zwj2px3C3L 1,1,2,2共9个，答案为 98求下列函数的定义域：1）2311xxyx；2）12log(2)xyx解：(2,3 2）由12log(2)0 x，得：021x，即：12x，函数的定义域为(1,2)9求下列函数的值域：1）242(14)yxxx；2）xxysin2sin2；3）22436xxyxx解：1）2(2)2yx14x，当2x时，max2y，当4x时，min2y 所给函数的值域为 2,22）由xxysin2sin2解得：22sin1yxy，由|sin|1x得22|11yy两边平方后整理，得：2310

21、30yy，解得：133x，故所给函数的值域为1,33 若1y，代入得：3x，25y函数的值域为：2|,15y yRyy且评注：本题中需要检验的原因是：函数22436xxyxx可化简为文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2

22、M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码

23、:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I1

24、0K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F

25、6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T

26、6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X

27、6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10

28、X7X4F2M65/9 1(3)2xyxx10已知函数12)(2axxxf在区间 1,2上的最大值为 4，求a的值解：22()()1yf xxaa1）当12a，即12a时，在2x时函数有最大值，(2)544fa，解得14a，适合；2）当12a，即12a时，在1x时函数有最大值，(1)224fa，解得1a，适合综上所述：14a或1a作业本A组1设IR，已知2()lg(32)f xxx的定义域为 F，函数()lg(1)lg(2)g xxx的定义域为 G，那么 GUIC F等于 B(，2 C(1，D(1，2U(2，提示：由2320 xx得：21xx或，F(，1(2，IC F1，2，又由1020 xx

29、得2x，G(2，GUIC F1，答案为 C2已知函数)(xf的定义域为 0，4，求函数)()3(2xfxfy的定义域为C）A 2,1 B1,2 C 2,1 D 1,2提示：由题意有404302xx解得12x，故此函数的定义域为 2，1，答案为 C3若a1,则11aa的最小值是 x2(y2xy30 当y 2时,(y224(y2(y30,解得2y310；当y2时,*）不成立综上所述：2y310.函数的值域为10(2,37求函数xxycoslg252的定义域解：由0cos0252xx得：)(222255Zkkxkx函数的定义域为33 5,)(,)(,522228已知函数2()23f xxx在0,a(

30、0)a上的最大值为 3，最小值为 2，求实数a的取值范围解：2()(1)2f xx，1）当12a，即2a时，2(1)2()233ff aaa，解得：20(aa或舍）；2）当12aa，即12a时，(1)2(0)3ff，适合题意；3）当1a时，2(0)3()232ff aaa，解得：1a舍）综上所述：12aB组1若函数()f x的定义域为 2，2，则函数()fx的定义域是 D）A4，4 B2，2 C 0，2 D 0，4zwj2px3C3L 提示：()fx中的x相当于()f x中的x，则22x，04x，答案为 D文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档

31、编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3

32、I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P

33、8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC

34、7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L

35、5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ

36、10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4

37、F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M67/9 2已知函数1()lg1xf xx的定义域为 A，函数()lg(1)lg(1)g xxx的定义域为 B，则下述关于 A、B的关系中，不正确的为 D）AAB BAB=B CA B=B DB错误!Azwj2px3C3L 提示：由101xx得：11x，|1

38、1Axx，由1010 xx得：11x，|11Axx,AB，显然，答案为 D3下列结论中正确的是 D）A当2x时，1xx的最小值为 2 B02x时，22xx无最大值C当0 x时，12xxD当1x时，1lg2lgxx提示：A中，12xx，但12xxx无解；B中，22xx为增函数，2x时可取得最大值；C中，0 x时不成立；D为真，答案为 D4函数(63)(02)yxxx的值域是0,3提示：2(2)3(2)3 32xxyxx，当且仅当022xxx，即1x时取等号又0y，故函数的值域为0,35已知函数22(1)1xyaxax的定义域是R,则实数a的范围是32232 2a提示：对x，2(1)10axax恒

39、成立，0a时，显然不符合题意；20(1)40aaa，解得：32232 2a6已知函数22()lg(1)(1)1,f xaxax若()f x的值域为(,)，求实数a的取值范围。解：设22(1)(1)1taxax,()(,)f x,(0,)t即t只要能取到(0,)上的任何实数即满足要求。由右图若2(1)0a，则22210513(1)4(1)0aaaa；若210a，则1a，当1,21atx时满足要求文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6

40、HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W

41、3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6

42、ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7

43、X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6

44、文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:C

45、S3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K

46、7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M68/9 当1,1at时不合，舍去）综上所述：513a7已知()f x的值域是34,89，试求函数()()12()yg xf xf x的值域解：34()89f x1112()94f x1112()32f x令1112()()32f xtt，则21()(1)2f xt2211(1)(1)122ytttminmax17173928tyty当时，当时，77,98y8已知二次函数

47、2()(0,)f xxbxc bcR若()f x的定义域为 1,0时，值域也是 1,0，符合上述条件的函数()f x是否存在？若存在，求出()f x的解读式；若不存在，请说明理由zwj2px3C3L 解：假设符合条件的()f x存在函数图像的对称轴是2bx，又0b，02b1）当1022b时，即01b，函数当2bx时，有最小值1，则22()1,1242(1)010bbbfcfbc0,4,().13bbcc或舍去2）当1122b时，即12b时，则2,2,()1,().200(1)0bbbfccf或都舍去3）当12b，即2b时，函数在 1,0上单调递增，则(1)1,2(0)00fbfc综上所述，符合

48、条件的函数有2个：22()1()2f xxf xxx或文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7

49、T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5

50、X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ10X7X4F2M6文档编码:CS3I10K7P8F6 HC7T6W3L5X6 ZJ1

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关键词：: 函数定义域值域

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