2022年一元二次不等式解法专题知识梳理及典型练习题 .pdf

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1、一元二次不等式解法专题一.一元二次不等式与相应的二次函数及一元二次方程的关系判别式 b24ac 0 0 0 二次函数 yax2bxc(a0)的图象一元二次方程 ax2bxc0(a0)的根有两相异实根x1，x2(x1x2)有两相等实根x1x2b2a没有实数根ax2bxc0(a0)的解集x|xx2或 xx1 x|x b2aRax2bxc0(a0)的解集 x|x1xx2二.穿针引线法例 1 解下列不等式：（1）xx2414（2）0822xx（3）0)3)(2(xx例 2 若 ax2bx10 的解集为 x|1x2，则 a_，b_例 3(穿针引线法）解不等式：(x-1)2(x+1)(x-2)(x+4)0

2、 例 4 不等式xx111的解集为（）Ax|x 0 Bx|x 1Cx|x 1 Dx|x 1 或 x0 解不 等 式 化 为，通 分 得，即，1x000111122xxxxxx20，x10，即 x1选 C例 5 与不等式023xx同解得不等式是（）A(x3)(2x)0B0 x21C 230 xxD(x3)(2x)0练习 1：1不等式 x23x20 的解集为()A(，2)(1，)B(2，1)C(，1)(2，)D(1,2)答案D 2(2011 广东)不等式 2x2x10 的解集是()A.12，1B(1，)C(，1)(2，)D.，12(1，)故原不等式的解集为，12(1，)答案D 3不等式 9x26x

3、10 的解集是()A.x|x 13B.13C.x|13 x13 DR答案B 4若不等式 ax2bx20 的解集为 x|2x14，则 ab()A28 B26 C28 D26 答案C 文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:

4、CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 H

5、E4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO

6、10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编

7、码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6

8、 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7

9、ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N55.函数 f(x)2x2x3log3(32xx2)的定义域为 _解析依题意知2x2x

10、30，32xx20，解得x 32或x1，1x3.1 x3.故函数 f(x)的定义域为 1,3)答案1,3)6.已知函数 f(x)x22x，x0，x22x，x0，解不等式 f(x)3.审题视点 对 x 分 x0、x0 进行讨论从而把f(x)3 变成两个不等式组解由题意知x0，x22x3或x0，x22x3，解得：x1.故原不等式的解集为 x|x1例不 等 式的 解 为或，则的 值 为7 1x|x1x2aaxx1Aa BaCa Da 12121212分 析可 以 先 将 不 等 式 整 理 为，转 化 为0()axx111(a1)x1(x1)0，根据其解集为 x|x 1 或 x2 可 知，即，且，a

11、10a12a1112a选 C例解 不 等 式8 237232xxx解先将原不等式转化为3723202xxx文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文

12、档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3

13、V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X

14、7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N

15、5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1

16、J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W

17、2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5即，所 以由 于，2123212314782222xxxxxxxx002xx12(x)022不等式进一步转化为同解不等式x22x30，即(x3)(x1)0，解

18、之得 3x1解集为 x|3x1 说明：解不等式就是逐步转化，将陌生问题化归为熟悉问题练习 2 1.(x+4)(x+5)2(2-x)302.解下列不等式(1);22123xx127314)2(22xxxx3.解下列不等式1x5x2)2(;3x1x1）（文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z

19、1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6

20、W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5

21、S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y

22、3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8

23、P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2

24、W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N54.解下列不等

25、式12log6log1log)2(;08254)1(21212121xxxx5 解不等式1)123(log2122xxx文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2

26、W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR

27、1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4

28、D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10

29、W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:

30、CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5文档编码:CR1Y3Z1J3V6 HE4D8P6W2X7 ZO10W2W5S3N5