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{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}2023-2024 学年第一学期福州市高中毕业班开门考
数 学 试 题
(完卷时间:120分钟;满分:150分)
本试卷分第Ⅰ卷(选择题)和第Ⅱ卷(非选择题)两部分。第Ⅰ卷1到2页,第Ⅱ卷3
至4页.
注意事项:
1. 答题前,考生务必在试题卷、答题卡规定的地方填写自己的准考证号、姓名.考生
要认真核对答题卡上粘贴的条形码的“准考证号、姓名”与考生本人准考证号、姓
名是否一致.
2. 第Ⅰ卷每小题选出答案后,用2B铅笔把答题卡上对应题目的答案标号涂黑.如需
改动,用橡皮擦干净后,再选涂其它答案标号.第Ⅱ卷用0.5毫米黑色签字笔在答
题卡上书写作答.在试题卷上作答,答案无效.
3. 考试结束,考生必须将答题卡交回.
第Ⅰ卷
一、单项选择题:本题共8小题,每小题5分,共40分.在每小题给出的四个选项中,只
有一项是符合题目要求的.
1
1. 已知复数z满足 1i ,则在复平面内,z对应的点在
z
A.第一象限 B.第二象限 C.第三象限 D.第四象限
【考查意图】本小题以复数为载体,主要考查复数的基本运算、几何意义等基础知识;
考查运算求解能力、推理论证能力;考查数学运算、逻辑推理等数学核心素养,体现基础性.
【答案】A.
1 1 1i
【解析】由 1i得z ,应选A.
z 1i 2
2. 已知集合A x x2<1 ,B x x>0 ,则AB
A.0,1 B.0, C.1, D.,
【考查意图】本小题以不等式为载体,主要考查集合运算等基础知识;考查运算求解能
力、推理论证能力;考查数学运算、逻辑推理等核心素养,体现基础性.
【答案】C.
【解析】A x 1<x<1 ,B x x>0 ,故AB (1,),应选C.
3. 已知点Px ,2在抛物线C:y2 4x上,则P到C的准线的距离为
0
A.4 B.3 C.2 D.1
1
{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}【考查意图】本小题以抛物线为载体,主要考查抛物线的图象和性质、直线与抛物线的
位置关系等基础知识;考查运算求解能力、推理论证能力;考查数形结合思想、化归与转化
思想;考查直观想象、逻辑推理、数学运算等核心素养,体现基础性.
【答案】C.
【解析】抛物线 y2 4x的准线为x1,由PC得x 1,故P到准线的距离为2,
0
应选C.
4. “二十四节气”是中国古代劳动人民伟大的智慧结
晶,其划分如图所示.小明打算在网上搜集一些与
二十四节气有关的古诗.他准备在春季的6个节气
与夏季的6个节气中共选出3个节气,若春季的节
气和夏季的节气各至少选出1个,则小明选取节气
的不同情况的种数是
A.90 B.180
C.270 D.360
【考查意图】本小题以二十四节气为载体,主要考查排列与组合等基础知识;考查运算
求解能力、推理论证能力和应用意识;考查数学运算、逻辑推理等核心素养,体现基础性和
应用性.
【答案】B.
【解析】根据题意可知,小明可以选取1春2夏或2春1夏.其中1春2夏的不同情况
有:C1 C2 90种;2春1夏的不同情况有:C2C1 90种,所以小明选取节气的不同情
6 6 6 6
况有:9090180种.应选B.
5. 一个正四棱台形油槽可以装煤油190000cm3,其上、下底面边长分别为60cm和40cm,
则该油槽的深度为
75
A. cm B.25cm C.50cm D.75cm
4
【考查意图】本小题以正四棱台形油槽为载体,主要考查空间几何体的体积等基础知识;
考查空间想象能力、推理论证能力、运算求解能力;考查数形结合思想、化归与转化思想;
考查直观想象、逻辑推理、数学运算等核心素养,体现基础性和应用性.
【答案】D.
【解析】设正四棱台的高,即深度为h cm,依题意,得190000 h 602 402 6040 ,
3
解得h75,应选D.
6. 一个袋子中有大小和质地相同的4个球,其中有2个红球,2个黄球,每次从中随机摸
出1个球,摸出的球不再放回.则第二次摸到黄球的条件下,第一次摸到红球的概率为
2
{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}1 1 2 3
A. B. C. D.
3 2 3 4
【考查意图】本小题主要考查条件概率、全概率公式等基础知识;考查推理论证能力、
运算求解能力与创新意识;考查化归与转化思想;考查数学建模、逻辑推理、数据分析等核
心素养,体现综合性、应用性与创新性.
【答案】C.
【解析】解法一:记第i次摸到红球为事件 A ,摸到黄球为事件B (i1,2),则
i i
PB PAP B A PB P B B 1 2 1 1 1 ,
2 1 2 1 1 2 1 2 3 2 3 2
PAB PAP B A 2 2 1 ,故P(A B ) P(A 1 B 2 ) 2 .应选C.
1 2 1 2 1 4 3 3 1 2 P(B ) 3
2
解法二:记第i次摸到红球为事件A ,摸到黄球为事件B (i1,2).由抽签的公平
i i
2 1 22 1 P(AB ) 2
性可知PB ,又PAB ,所以P(A B ) 1 2 .应选C.
2 4 2 1 2 43 3 1 2 P(B ) 3
2
1
7. 已知a ,bln 2,cln55,则
e
A.a>b>c B.b>c>a C.a>c>b D.c>a>b
【考查意图】本小题以数的大小比较为载体,主要考查函数与导数等基础知识;考查运
算求解能力、推理论证能力、应用意识;考查数学建模、数学运算、逻辑推理等核心素养,
体现基础性、应用性和综合性.
【答案】A.
1 lne ln2 ln4 ln5 lnx
【解答】解法一:a ,bln 2 ,cln55 ,令 f x ,
e e 2 4 5 x
1lnx
fx ,当x≥e时,fx≤0,故 f x在区间e,上单调递减,所以a>b>c.
x2
解法二:因为 2 1025 1032>1025 55 ,所以
ln 2>ln55,即b>c.
在同一坐标系中作出函数 f x2x,gx x2的图象,
如图所示,由图可知, f e< ge,即2e<e2 ,所以
e 2 1 1 1 1 1
22e <e2e,即22 <ee ,所以 ln2< lne ,即b<a.
2 e e
lnx 1lnx
(令 f x , fx ,当0 xe时, fx0,故 f x在区间0,e上
x x2
1 lne ln2
单调递增,所以a ln 2 b.)
e e 2
3
{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}综上,a>b>c.应选A.
8. 若定义在R上的函数 f x sinxcosx(>0)的图象在区间 0,上恰有5条
对称轴,则的取值范围为
17 21 17 25 17 25 33 41
A. , B. , C. , D. ,
4 4 4 4 4 4 4 4
【考查意图】本小题以三角函数为载体,考查三角函数的图象与性质、三角恒等变换等
基础知识;考查抽象概括能力、推理论证能力、应用意识;考查数形结合思想;考查直观想
象、逻辑推理、数学运算等核心素养,体现基础性和综合性.
【答案】A.
π
【解析】由已知, f x 2sin x ,
4
π (4k1)π
令x =kπ ,kZ,得x ,kZ,
4 2 4
(4k1)π
依题意知,有5个整数k满足0≤ ≤π,即0≤4k1≤4,所以k 0,1,
4
17 21
2,3,4,则441≤4<451,故 ≤< ,应选A.
4 4
二、多项选择题:本题共4小题,每小题5分,共20分.在每小题给出的四个选项中,有
多项符合题目要求.全部选对的得5分,部分选对的得2分,有选错的得0分.
9. 某市抽查一周空气质量指数变化情况,得到一组数据:80,76,73,82,86,75,81.以
下关于这组数据判断正确的有
A.极差为13 B.中位数为82 C.平均数为79 D.方差为124
【考查意图】本小题主要考查极差、中位数、平均数、方差等基础知识;考查推理论证
能力、运算求解能力;考查化归与转化思想;考查数据分析等核心素养,体现基础性.
【答案】AC.
10. 已知圆M: x2 y2 1,直线l:yk x 3 1,则
3
A.l恒过定点 3,1 B.若l平分圆周M,则k
3
C.当k 3时,l与圆M相切 D.当 3<k< 3时,l与圆M相交
【考查意图】本小题以直线与圆为载体,考查直线的方程、圆的方程、直线与圆的位置
关系等基础知识;考查运算求解能力;考查直观想象、逻辑推理等核心素养;体现基础性和
综合性.
【答案】BC.
【解析】依题意,l恒过定点 3,1 ,选项A错误;
4
{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}3
若l平分圆周M,则l经过圆M的圆心0,0,代入直线方程得k ,选项B正确;
3
3k1
圆心O0,0到l的距离d ,当k 3时,d 1r,l与圆M相切,选项C
k2 1
2
正确;若l与圆M相交,则d<1,即 3k1 <k2 1,即0<k< 3,故选项D错误.
综上,应选BC.
11. 已知函数 f x x3 3ax2有两个极值点.则
A. f x的图象关于点0,2 对称 B. f x的极值之和为4
C.aR,使得 f x有三个零点 D.当0<a<1时, f(x)只有一个零点
【考查意图】本小题以三次函数为载体,主要考查函数与导数等基础知识;考查运算求
解能力、推理论证能力、应用意识;考查数学建模、数学运算、逻辑推理等核心素养,体现
基础性、应用性和综合性.
【答案】ACD.
【解答】 f x的图象可由奇函数gx x3 3ax的图象向上平移2个单位长度得到,
故 f x的图象关于点0,2对称,选项A正确.
设 f x 的极值点分别为 x ,x ( x <x ),则由对称性可知 x x 0 ,故
1 2 1 2 1 2
f x f x 224,即 f x的极值之和为4,选项B错误.
1 2
依题意,方程 fx3x2 3a0有两异根,则a>0,x a,x a, f x在区间
1 2
,a上单调递增,在区间 a,a 上单调递减,在区间 a, 单调递增.由图象
可知,当 f x >0> f x 时,f x的图象与x轴有3个交点,即 f x有3个零点,选项
1 2
C正确.当0<a<1时, f a a a 3a a 22 1a a >0,此时 f x只有一个零
点,选项D正确.
综上,应选ACD.
12. 已知正四棱柱ABCDABCD 的底面边长为2,球O与正四棱柱的上、下底面及侧棱
1 1 1 1
都相切.P为平面CDD 上一点,且直线BP与球O相切,则
1
A.球O的表面积为4π B.直线BD 与BP夹角等于45
1
C.该正四棱柱的侧面积为16 2 D.侧面ABB A与球面的交线长为2π
1 1
【考查意图】本小题以正四棱柱为载体,主要考查球、直线与平面的位置关系等基础知
识;考查空间想象能力、推理论证能力、运算求解能力;考查化归与转化思想;考查直观想
象、逻辑推理等核心素养,体现基础性、应用性和综合性.
【答案】BCD.
5
{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}【解答】如图,设球O与下底面相切于点O ,则OO 平面ABCD,连接OA,则OAO
1 1 1 1
为直线OA与平面 ABCD 所成的角.因为球 O 与正四棱柱的侧棱相切,所以其半径
ROO O A 2,所以S 4π28π,四棱柱的侧面积为242 2 16 2,故选项
1 1 表
A错误,C正确.
依题意, BB ,BP 均为球O 的切线, BD 经过球心O,所以BBD PBD ,又
1 1 1 1 1
BD 2 2 BB ,所以PBD BBD 45,选项B正确.
1 1 1 1 1 1
对于选项D,棱AA 的中点F ,即球O与棱AA 的切点应为
1 1
交线上的点,故交线应为过F 的圆.截面圆的圆心即为矩形
1
ABB A的中心E,在Rt△OEF 中,OF R 2,OE BC 1,
1 1 2
所以截面圆半径r EF 211,周长为2π,该选项正确.
综上,应选BCD.
第Ⅱ卷
注意事项:
用0.5毫米黑色签字笔在答题卡上书写作答.在试题卷上作答,答案无效.
三、填空题:本大题共4小题,每小题5分,共20分.
13. 已知向量a1,2,b1,2,若ab,则实数的值为 .
【考查意图】本小题以平面向量为载体,主要考查平面向量的基本运算等基础知识;考
查运算求解能力、推理论证能力;考查数学运算、逻辑推理、直观想象等核心素养,体现基
础性.
【答案】5.
【解析】由ab得1220,解得5.
14. 将圆周16等分,设每份圆弧所对的圆心角为,则sincos的值为 .
【考查意图】本小题以圆的等分为载体,考查三角恒等变换等基础知识;考查推理论证
能力,抽象概括能力;考查逻辑推理等核心素养;体现基础性与应用性.
2
【答案】 .
4
1 1 π 2
【解析】依题意,得 ,所以sincos sin2 sin .
8 2 2 4 4
15. 已知定义域为R的函数 f x同时具有下列三个性质,则 f x .(写出一个
满足条件的函数即可)
① f x y f x f y;② fx是偶函数;③当x y>0时, f x f y<0.
6
{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}【考查意图】本小题以函数的性质为载体,考查函数的奇偶性、函数与导数等基础知识;
考查推理论证能力;考查逻辑推理等核心素养;体现基础性、综合性与应用性.
【答案】x(答案不唯一,kxk<0均可).
x2 y2
16. 已知双曲线C: 1(a>0,b>0)的左焦点为F ,两条渐近线分别为l ,l .点
a2 b2 1 2
A在l 上,点B在l 上,且点 A位于第一象限,原点O与B关于直线 AF 对称.若
1 2
AF 2b,则C的离心率为 .
【考查意图】本小题以双曲线为载体,主要考查双曲线的离心率、双曲线的图象和性质、
直线与双曲线的位置关系等基础知识;考查运算求解能力、推理论证能力;考查数形结合思
想、化归与转化思想;考查直观想象、逻辑推理、数学运算等核心素养,体现基础性和综合
性.
【答案】2.
b
【解答】依题意,l 的方程为 y x, AF l ,设垂足为 P ,则 FP b.因为
1 a 2
AF 2b 2 FP ,所以点F,A关于直线l 对称,FOPAOP,又l ,l 关于y轴对称,
2 1 2
1 b b2
所以l 的倾斜角为 18060,故 tan60 3,所以离心率e 1 2.
1 3 a a2
四、解答题:本大题共6小题,共70分.解答应写出文字说明、证明过程或演算步骤.
17. (本小题满分10分)
已知等比数列a 的前n项和为S ,且a S 2.
n n n1 n
(1)求a 的通项公式;
n
(2)若b log a ,求数列b 的前n项和T .
n 2 2n1 n n
【命题意图】本小题主要考查等差数列、等比数列、递推数列及数列求和等基础知识,
考查运算求解能力、逻辑推理能力和创新能力等,考查化归与转化思想、分类与整合思想、
函数与方程思想、特殊与一般思想等,考查逻辑推理、数学运算等核心素养,体现基础性和
综合性.满分10分.
a S 2,
【解答】(1)解法一:由a S 2得 2 1 ········································1分
n1 n a S 2,
3 2
设等比数列a 的公比为q,
n
所以
a
a
1
1
q
q
2
1
q
2
1
,
2,
················································································2分
a 2, a 2,
解得 1 或 1 (舍去).·························································· 4分
q2, q0
7
{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}所以a 2n.··························································································5分
n
(2)b log a log 22n1 2n1,························································7分
n 2 2n1 2
故b 1,b b 2n1 2(n1)1 2(n≥2),
1 n n1
所以b 是首项为1,公差为2的等差数列,
n
nb b n12n1
所以T 1 n n2.······················································10分
n 2 2
解法二:(1)因为a S 2,①
n1 n
所以当n≥2时,a S 2,②·······························································1分
n n1
①-②得a 2a ,················································································ 2分
n1 n
a
所以等比数列a 的公比q n1 2.························································3分
n a
n
由①式得a a 2,得a 2,·································································4分
2 1 1
所以a 2n.··························································································5分
n
(2)T b b b
n 1 2 n
log a log a log a
2 1 2 3 2 2n1
log aa a ········································································7分
2 1 3 2n1
log 2132n1
2
12n1n
log 2 2
2
n2.·······················································································10分
18. (本小题满分12分)
π
记△ABC的内角A,B,C所对的边分别为a,b,c,已知b 2 ,B .
6
(1)若c2,求a;
(2)求△ABC面积的最大值.
【命题意图】本小题主要考查正弦定理、余弦定理及三角恒等变换等基础知识,考查逻
辑推理能力、运算求解能力等,考查化归与转化思想、函数与方程思想、数形结合思想等,
考查数学运算、逻辑推理等核心素养,体现基础性和综合性.满分12分.
π
【解答】解法一:(1)因为b 2 ,c2,B ,
6
根据余弦定理得b2 a2 c2 2accosB,
2 π
所以 2 a2 22 4acos ,···································································3分
6
8
{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}即a2 2 3a20,
解得a 31.······················································································6分
(2)根据余弦定理,得b2 a2 c2 2accosB,
π
所以2a2 c2 2accos a2 c2 3ac≥2ac 3ac 2 3 ac,·················8分
6
(当且仅当ac 31时取等号),···························································9分
2
即ac≤ 2 2 3 ,
2 3
1 1 π 1 1 2 3
所以△ABC面积S acsinB acsin ac≤ 2 2 3 ,
△ABC
2 2 6 4 4 2
2 3
即△ABC面积的最大值为 .·························································12分
2
π
解法二:(1)因为b 2,c2且B ,
6
b c
根据正弦定理,得 ,
sinB sinC
2 2 2
所以 ,即sinC ,·····························································1分
π sinC 2
sin
6
π 5π
因为cb,所以CB,所以 C ,
6 6
π 3π
所以C 或C ,··············································································2分
4 4
π π π 1 2 3 2 6 2
当C 时,sinAsinBCsin ,
4 6 4 2 2 2 2 4
a b
根据正弦定理,得 ,
sinA sinB
6 2
2
所以a bsinA 4 31;······················································4分
sinB π
sin
6
3π π 3π 1 2 3 2 6 2
当C 时,sinAsinBCsin
,
4 6 4 2 2 2 2 4
a b
根据正弦定理,得 ,
sinA sinB
6 2
2
所以a bsinA 4 31;
sinB π
sin
6
9
{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}综上,a 31.···················································································6分
(2)略,同解法一.
π
解法三:(1)因为b 2 ,c2且B ,
6
b c
根据正弦定理,得 ,
sinB sinC
2 2 2
所以 ,即sinC ,·····························································1分
π sinC 2
sin
6
π 5π
因为cb,所以CB,所以 C ,
6 6
π 3π
所以C 或C ,··············································································2分
4 4
π π π 7π
当C 时,AπBCπ ,
4 6 4 12
a b
根据正弦定理,得 ,
sinA sinB
7π
2sin
所以a bsinA 12 2 2sin π π 2 2 sin π cos π cos π sin π
sinB π 3 4 3 4 3 4
sin
6
π π π π
2 2sin cos cos sin 31;······················································4分
3 4 3 4
3π π 3π π
当C 时,AπBCπ ,
4 6 4 12
a b
根据正弦定理,得 ,
sinA sinB
π
2sin
所以a bsinA 12 2 2sin π π 2 2 sin π cos π cos π sin π
sinB π 3 4 3 4 3 4
sin
6
π π π π
2 2sin cos cos sin 31;
3 4 3 4
综上,a 31.···················································································6分
a c b 2
(2)根据正弦定理,得 2 2 ,
sinA sinC sinB π
sin
6
所以a2 2sinA,c2 2sinC ,
10
{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#} 2 5π 1 3
即ac 2 2 sinAsinC8sinAsin A 8sinA
cosA sinA
6 2 2
1cos2A
2sin2A4 3sin2A 2sin2A4 3 2sin2A2 3cos2A2 3
2
1 3 π
4
sin2A cos2A
2 3 4sin2A 2 3,·································· 8分
2 2 3
5π π π 4π
因为0 A ,所以 2A ,
6 3 3 3
π π 5π π
所以当2A ,即A 时,sin2A 取得最大值为1,即ac最大值为42 3,
3 2 12 3
1 1 π 1 1 2 3
所以△ABC面积S acsinB acsin ac≤ 42 3 ,
△ABC
2 2 6 4 4 2
2 3
即△ABC面积的最大值为 .·························································12分
2
19. (本小题满分12分)
国际上常采用身体质量指数(BodyMassIndex,缩写BMI)来衡量人体肥瘦程度,其
体重(单位:kg)
计算公式是BMI .为了解某公司员工的身体肥瘦情况,研究人员从该公
身高(2 单位:m2)
司员工体检数据中,采用比例分配的分层随机抽样方法抽取了50名男员工、30名女员工的
身高和体重数据.计算得到他们的BMI值,并根据“中国成人的BMI数值标准”简称“指
标”整理得到如下结果:
指标
偏瘦 正常 偏胖 肥胖
人数
(BMI<18.5) (18.5≤BMI<24) (24≤BMI<28) (BMI≥28)
性别
男 12 17 11 10
女 9 11 7 3
(1)若该公司男员工有1500名,则该公司共有多少名员工?
(2)以频率估计概率,分别从该公司男、女员工中各随机抽取2名员工,求抽到的员
工中至少有一名是肥胖的概率.
【命题意图】本小题主要考查分层抽样、独立事件的概率、互斥事件、对立事件的概率
等基础知识;考查数学建模能力,运算求解能力,逻辑推理能力,创新能力以及阅读能力等;
考查统计与概率思想、分类与整合思想等;考查数学抽象,数学建模和数学运算等核心素养;
体现应用性和创新性.满分12分.
【解】(1)设该公司共有x名员工,
1500 50
依题意得 ,·········································································3分
x 5030
11
{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}解得x2400,
所以该公司共有2400名员工.·································································· 5分
40 4
(2)依题意,事件“抽到一名男员工不为肥胖”的概率为 ,事件“抽到一名女
50 5
27 9
员工不为肥胖”的概率为 ,···································································7分
30 10
4 4 16
由事件的独立性,得抽到的两个男员工都不存在肥胖的概率为 ,·········8分
5 5 25
9 9 81
抽到的两个女员工都不存在肥胖的概率为 ,·································9分
10 10 100
设事件M为“抽到的员工中至少有一名是肥胖”,则事件M 为“抽到的员工都不存在
肥胖”,
81 16 324
所以P M ,···································································10分
100 25 625
324 301
所以PM1 ,
625 625
301
所以抽到的员工中至少有一名是肥胖的概率为 .·····································12分
625
20. (本小题满分12分)
如图,在底面为菱形的四棱锥M ABCD中,ADBDMB2,MAMD 2 .
(1)求证:平面MAD平面ABCD;
(2)已知MN 2NB,求直线BN 与平面ACN所成角的正弦值.
【命题意图】本小题主要考查直线与直线、直线与平面、平面与平面的位置关系,直
线与平面所成角等基础知识;考查空间想象能力,逻辑推理能力,运算求解能力等;考查化
归与转化思想,数形结合思想,函数与方程思想等;考查直观想象,逻辑推理,数学运算等
核心素养;体现基础性和综合性.满分12分.
【解答】(1)取AD的中点为O,连结OM,OB,
因为四边形ABCD是为菱形,且ADBD2,
所以△ABD为正三角形,所以BO AD,且BO 3 .
因为MAMD 2,所以MO AD,·····················································2分
12
{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#} 2
所以MO MA2 AO2 2 12 1,
又因为MB2,所以MO2 BO2 MB2,
所以MOBO,···················································································4分
因为ADBOO,AD平面ABCD,BO平面ABCD
所以MO平面ABCD,········································································5分
又因为MO平面MAD,
所以平面MAD平面ABCD.································································6分
(2)由(1)知,OA,OB, OM 两两垂直,故以O为坐标原点,分别以OA,OB,OM 为x,y,
z轴的正方向建立如图所示的空间直角坐标系Oxyz.
则A1,0,0,B 0, 3,0 , C 2, 3,0 , M 0,0,1 , N 0, 2 3 , 1 ,·························7分
3 3
所以C A 3, 3,0 , C N 2, 3 , 1 , C B 2,0,0 ,
3 3
设平面ACN的法向量为n
x,y,z
,
3x 3y0,
nCA0,
则
即
3 1
nCN 0, 2x y z0,
3 3
取x1,则n 1, 3,3 .·····································································9分
因为BM 0, 3,1 ,
BM n 33 3 13
则cos BM ,n ,··············································11分
BM n 2 13 13
3 13
所以直线BN 与平面ACN所成角的正弦值为 .··································· 12分
13
21. (本小题满分12分)
13
{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}x2 y2
已知椭圆E: 1的右焦点为F ,左、右顶点分别为A,B.点C在E上,
4 3
P4,y ,Q 4,y 分别为直线AC,BC上的点.
P Q
(1)求y y 的值;
P Q
(2)设直线BP与E的另一个交点为D,求证:直线CD经过F .
【命题意图】本小题主要考查椭圆的标准方程及简单几何性质,直线与圆、椭圆的位置
关系,平面向量等基础知识;考查运算求解能力,逻辑推理能力,直观想象能力和创新能力
等;考查数形结合思想,函数与方程思想,化归与转化思想等;考查直观想象,逻辑推理,
数学运算等核心素养;体现基础性,综合性与创新性.满分12分.
【解答】(1)依题意,A2,0,B2,0.··············································· 1分
x2 y2
设Cx ,y ,则 1 1 1,
1 1 4 3
y 6y
直线AC 方程为y 1 x2,令x4得y 1 ,·····························2分
x 2 P x 2
1 1
y 2y
直线BC方程为y 1 x2,令x4得y 1 ,·····························3分
x 2 Q x 2
1 1
12y2
所以y y 1
P Q x2 4
1
x2
1231 1
4
········································································4分
x2 4
1
9,
即y y 的值为9.·············································································5分
P Q
(2)设Dx ,y ,P4,t,则
2 2
t t
直线AP方程为y x2,直线BP的方程为y x2,
6 2
t
由 y 6 x2, 得 t2 27 x2 4t2x4t2 1080,···································6分
3x2 4y2 12
4t2 108 542t2 t 18t
所以2x ,即x ,故 y x 2 .················7分
1 t2 27 1 27t2 1 6 1 27t2
t
由 y 2 x2, 得 t2 3 x2 4t2x4t2 120,
3x2 4y2 12
4t2 12 2t2 6 t 6t
所以2x ,即x ,故y x 2 .·····················8分
2 t2 3 2 t2 3 2 2 2 t2 3
14
{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}所以x 1y x 1y
1 2 2 1
273t2 6t t2 9 18t
27t2 t2 3 t2 3 27t2
6t 273t23t227
0,···························································10分
t2 3 27t2
又F1,0,所以向量FCx 1,y 与FDx 1,y 共线,···················11分
1 1 2 2
所以直线CD经过F .··········································································12分
解法二:(1)依题意,A2,0,B2,0.··············································· 1分
x2 y2
设Cx ,y ,则 1 1 1,
1 1 4 3
y y
所以k k 1 1 ·····································································2分
AC BC x 2 x 2
1 1
y2
1
x2 4
1
x2
31 1
4
·······································································3分
x2 4
1
3
.············································································4分
4
3 y y
即 k k P Q ,故y y 的值为9.·····································5分
4 AP BQ 42 42 P Q
(2)设Cx ,y ,Dx ,y ,P4,t.
1 1 2 2
要证直线CD经过F1,0,
只需证向量FCx 1,y 与FDx 1,y 共线,··································6分
1 1 2 2
即证x 1y x 1y .(*)·······························································7分
1 2 2 1
x2 y2 22 02 y 3 x 2 y
因为 1 1 1 ,所以k 1 1 P ,
4 3 4 3 AC x 2 4 y 6
1 1
y 3 x 2 y
同理可得k 2 2 P ,···················································9分
BD x 2 4 y 2
2 2
k
x 2y
1
所以 AC 2 1 ,即x y 3x y 6y 2y 0,①
k x 2y 3 1 2 2 1 1 2
BD 1 2
同理可得3x y x y 2y 6y 0,②·················································10分
1 2 2 1 1 2
①-②得4x y 4x y 4y 4y 0,即x 1y x 1y .···················11分
1 2 2 1 1 2 1 2 2 1
所以(*)式成立,命题得证.·······························································12分
15
{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}22. (本小题满分12分)
已知函数 f xlnxa,记曲线y f x在点 x ,f x 处的切线为l ,l在x轴上的
1 1
截距为x (x >0).
2 2
(1)当x e,a1时,求切线方程;
1
(2)证明: x ea ≥ x ea .
1 2
【命题意图】本小题主要考查导数,函数的单调性、零点、不等式等基础知识;考查逻
辑推理能力,直观想象能力,运算求解能力和创新能力等;考查函数与方程思想,化归与转
化思想,分类与整合思想等;考查逻辑推理,直观想象,数学运算等核心素养;体现基础性、
综合性和创新性.满分12分.
1
【解答】(1) f(x) ,··········································································1分
x
当x e,a1时, f x lne10,即切点为e,0,································2分
1 1
1
所以所求切线斜率k fe ,································································3分
e
1 1
所以所求的切线方程为y (xe),即y x1.········································4分
e e
(2)由于 f x lnx a,
1 1
1
所以切线l的方程为y(lnx a) (xx ).··············································5分
1 x 1
1
1
令y 0,得(lnx a) (xx ),解得x x x (lnx a).(*)·················6分
1 x 1 2 1 1 1
1
由x 0,得x ea1.·············································································7分
2 1
构造函数gxxx(lnxa),
所以g xaln x,
所以当0<x<ea时,gx>0,gx单调递增;当x>ea时,gx<0,gx单
调递减.故gx g ea ea.
max
所以x 2ea.···························································································8分
若x 1ea,由(*)式知x 1x
2
,
所以x 1x 2ea,
故 x
1
ea x
2
ea .··············································································10分
若x >ea,则 x ea x ea (x ea)(ea x ) (x x )2ea,
1 1 2 1 2 1 2
16
{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}所以 x ea x ea 2x x (lnx a)2ea .
1 2 1 1 1
构造函数(x)2xx(lnxa)2ea(ea xea1),
所以(x)(1a)lnx0,
故(x)在区间(ea ,ea1)上单调递增,
所以(x)(ea)0,
所以2x x (lnx a)2ea 0,即
1 1 1
所以 x ea x ea 0,即 x ea x ea .
1 2 1 2
综上,不等式成立 x
1
ea x
2
ea 成立(当且仅当x
1
ea时取等号).············12分
17
{#{QQABKYaAggCgAAAAARgCEQUgCEGQkAGAAAgOwFAEoAIBCBNABAA=}#}