摘要:满足,求的取值范围. 得分评卷人

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一、选择题(每小题5分,共50分)

  1.C  2.B  3.D  4.A  5.C  6.B  7.A  8.C  9.B  10.D

二、填空题(每小题4分.共24分)

  11.5  12.4   13.3825   14.6ec8aac122bd4f6e 15.6ec8aac122bd4f6e   16.3

三.解答题(本大题共6小题,共76分)

17.(本题12分)

解:(Ⅰ)∵6ec8aac122bd4f6e

6ec8aac122bd4f6e          ………………………(2分)

6ec8aac122bd4f6e    ………………………(3分)

6ec8aac122bd4f6e              ……………………(4分)

∵在6ec8aac122bd4f6e中,6ec8aac122bd4f6e

6ec8aac122bd4f6e                             ………………………(5分)

(Ⅱ)设6ec8aac122bd4f6e分别是6ec8aac122bd4f6e6ec8aac122bd4f6e的对边,

∵?6ec8aac122bd4f6e

6ec8aac122bd4f6e

6ec8aac122bd4f6e    ①                                          ……………………(6分)

由正弦定理:6ec8aac122bd4f6e,得 6ec8aac122bd4f6e             ……………………(7分)

6ec8aac122bd4f6e

6ec8aac122bd4f6e    ②                                          ……………………(8分)

由①②解得6ec8aac122bd4f6e                                    ……………………(9分)

由余弦定理,得6ec8aac122bd4f6e                       ………………(10分)

                 6ec8aac122bd4f6e

                 6ec8aac122bd4f6e                                       ………………(11分)

6ec8aac122bd4f6e,即边6ec8aac122bd4f6e的长为6ec8aac122bd4f6e。                              ……………………(12分)

 

18.(本题12分]

解:(Ⅰ)∵6ec8aac122bd4f6e是偶函数,

6ec8aac122bd4f6e,即6ec8aac122bd4f6e            ……(2分)

6ec8aac122bd4f6e

6ec8aac122bd4f6e                                  ………………………………(4分)

6ec8aac122bd4f6e对一切6ec8aac122bd4f6e恒成立。

6ec8aac122bd4f6e                                    ……………………………………(6分)

(Ⅱ)由6ec8aac122bd4f6e                            ………………(7分)

6ec8aac122bd4f6e

  6ec8aac122bd4f6e                                         …………………(8分)

  6ec8aac122bd4f6e

错误!不能通过编辑域代码创建对象。6ec8aac122bd4f6e                                           ……………………(10分)

6ec8aac122bd4f6e6ec8aac122bd4f6e                                    …………………(11分)

6ec8aac122bd4f6e6ec8aac122bd4f6e

∴若使方程6ec8aac122bd4f6e有解,则6ec8aac122bd4f6e的取值范围是6ec8aac122bd4f6e6ec8aac122bd4f6e          ………………(12分)

 

19.(本题12分)

解:(Ⅰ) ∵6ec8aac122bd4f6e分别是6ec8aac122bd4f6e的中点,

6ec8aac122bd4f6e6ec8aac122bd4f6e                                  ……………………(1分)

6ec8aac122bd4f6e平面6ec8aac122bd4f6e,6ec8aac122bd4f6e平面6ec8aac122bd4f6e

6ec8aac122bd4f6e平面6ec8aac122bd4f6e                                   …………………………(2分)

6ec8aac122bd4f6e平面6ec8aac122bd4f6e6ec8aac122bd4f6e平面6ec8aac122bd4f6e6ec8aac122bd4f6e平面6ec8aac122bd4f6e

6ec8aac122bd4f6e                                          …………………………(4分)

6ec8aac122bd4f6e6ec8aac122bd4f6e的中点,

6ec8aac122bd4f6e6ec8aac122bd4f6e的中点.

6ec8aac122bd4f6e                               ………………………(5分)

6ec8aac122bd4f6e

∴四边形6ec8aac122bd4f6e是平行四边形                         …………………………(6 分)

(Ⅱ)当6ec8aac122bd4f6e时,平面6ec8aac122bd4f6e平面6ec8aac122bd4f6e                   …………………(8分)

6ec8aac122bd4f6e上取一点,6ec8aac122bd4f6e连接6ec8aac122bd4f6e

6ec8aac122bd4f6e6ec8aac122bd4f6e时,

6ec8aac122bd4f6e6ec8aac122bd4f6e

6ec8aac122bd4f6e

       6ec8aac122bd4f6e

       6ec8aac122bd4f6e

即当6ec8aac122bd4f6e时,6ec8aac122bd4f6e6ec8aac122bd4f6e                    ……………………(9分)

6ec8aac122bd4f6e6ec8aac122bd4f6e6ec8aac122bd4f6e

6ec8aac122bd4f6e平面6ec8aac122bd4f6e                                       ……………………(10分)

6ec8aac122bd4f6e

6ec8aac122bd4f6e平面6ec8aac122bd4f6e                                 ……………………………(11分)

6ec8aac122bd4f6e平面6ec8aac122bd4f6e

∴平面6ec8aac122bd4f6e6ec8aac122bd4f6e平面6ec8aac122bd4f6e                     …………………………………(12分)

 

 

 

20.(本题12分)

解:(Ⅰ) ∵6ec8aac122bd4f6e

6ec8aac122bd4f6e                           ………………………………(2分)

6ec8aac122bd4f6e在区间6ec8aac122bd4f6e上为减函数

6ec8aac122bd4f6e≤O在区间6ec8aac122bd4f6e上恒成立                      …………………………(3分)

6ec8aac122bd4f6e是开口向上的抛物线

6ec8aac122bd4f6e6ec8aac122bd4f6e        6ec8aac122bd4f6e6ec8aac122bd4f6e      6ec8aac122bd4f6e6ec8aac122bd4f6e

∴只需              即                               …………………………(5分)

        6ec8aac122bd4f6e6ec8aac122bd4f6e       6ec8aac122bd4f6e6ec8aac122bd4f6e

6ec8aac122bd4f6e6ec8aac122bd4f6e6ec8aac122bd4f6e                             ………………………………………(6分)

6ec8aac122bd4f6e6ec8aac122bd4f6e                                      

6ec8aac122bd4f6e(Ⅱ)当6ec8aac122bd4f6e时,                     

                                      

∴存在6ec8aac122bd4f6e,使得6ec8aac122bd4f6e

6ec8aac122bd4f6e在区间6ec8aac122bd4f6e内有且只有一个极小值点                      ……………(8分)

6ec8aac122bd4f6e6ec8aac122bd4f6e                   

6ec8aac122bd4f6e6ec8aac122bd4f6e时                      

 

∴存在6ec8aac122bd4f6e,使得6ec8aac122bd4f6e

6ec8aac122bd4f6e在区间6ec8aac122bd4f6e内有且只有一个极大值点                     ……………(10分)

6ec8aac122bd4f6e6ec8aac122bd4f6e6ec8aac122bd4f6e时,由(Ⅰ)可知6ec8aac122bd4f6e在区间6ec8aac122bd4f6e上为减函数

6ec8aac122bd4f6e在区间6ec8aac122bd4f6e内没有极值点.

综上可知,当6ec8aac122bd4f6e6ec8aac122bd4f6e时,6ec8aac122bd4f6e在区间6ec8aac122bd4f6e内的极值点个数为6ec8aac122bd4f6e

6ec8aac122bd4f6e6ec8aac122bd4f6e6ec8aac122bd4f6e时,6ec8aac122bd4f6e在区间6ec8aac122bd4f6e内的极值点个数为6ec8aac122bd4f6e          ………(12分)

 

6ec8aac122bd4f6e21.(本题14分)

解:(Ⅰ)设椭圆的长半轴长为6ec8aac122bd4f6e,短半轴长6ec8aac122bd4f6e,半焦距为6ec8aac122bd4f6e

由离心率6ec8aac122bd4f6e,得6ec8aac122bd4f6e

6ec8aac122bd4f6e

6ec8aac122bd4f6e            ①                                     …………………(2分)

∵直线6ec8aac122bd4f6e的方程为6ec8aac122bd4f6e,原点6ec8aac122bd4f6e到直线6ec8aac122bd4f6e的距离为6ec8aac122bd4f6e

6ec8aac122bd4f6e  ②                                     …………………(4分)

①代人②,解得6ec8aac122bd4f6e                            ………………………(6分)

∴椭圆的标准方程为6ec8aac122bd4f6e                        …………………………(7分)

(Ⅱ) ∵6ec8aac122bd4f6e

∴?=6ec8aac122bd4f6e

∴?=?(-)=2                                    …………………(9分)

6ec8aac122bd4f6e,则6ec8aac122bd4f6e,即6ec8aac122bd4f6e                     ………………(10分)

6ec8aac122bd4f6e

∴?=2

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