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高二数学试卷参考答案与评分细则
一、选择题:本题共8小题,每小题5分,共40分.
1.D 2.C 3.A 4.C
5.C 6.B 7.D 8.B
1【解析】A[1,4],B [0,2],所以AB [0,2],故选D.
2【解析】由极大值点的定义结合导函数图像可知个数为2个,故选C.
3【解析】若 f(a) f(b)0,由零点存在性定理知 f(x)在 a,b 上有零点,充分性满足;取 f(x) x2 1,
x[2,2],必要性不满足,故选A.
a
4【解析】由等比数列的性质可知T a9 512,所以a 2,所以a a 5 a q2 2a 4,故选C.
9 5 5 3 7 q2 5 5
ab 1 1 1
5【解析】由投影向量的定义和公式可知a在b的投影向量为 b (0,1,1)(0, , ),故选C.
2 2 2 2
b
6【解析】易知D在椭圆内部,所以|PF ||PD|4|PF ||PD|,由几何关系可知|PF ||PD|[1,1],
1 2 2
所以最小值为3,故选B.
7【解析】当首位大于2时有2A3 48种;当首位为2,第二位非0时有3A2 18种;当首位为2,第二位为0
4 3
时有2A1 4种;综上,总共有48+18+4=70种,故选D.
2
8【解析】对于a、b,同时12次方可得34与53,易知34 53,所以ab;对于b、c,同时4e次方可得5e与
ln3 1 ln3 1
e4,由题干可知52e 55 e8,所以5e e4,即bc;对于a、c,同时取对数可得 与 ,易知 ,
3 e 3 e
所以ac,综上可得acb,故选B.
二、选择题:本题共3小题,每小题6分,共18分.在每小题给出的选项中,有多项符合题目要求.全部选对的
得6分,部分选对的得部分分,有选错的得0分.
9.ACD 10.ACD 11.ABC
说明:多选题有错选得0分,第9、10、11题选对一个答案给2分,选对两个答案给4分,选对3个答案给6分.
1 2
9【解析】对于选项A,由方差的运算性质可知D(3X 1)9D(X)910 20,故A正确;
3 3
(x)2
1
对于选项B,由正态密度函数 f(x) e 22 可知,当不变时,越小,函数值越大,该正态分布对
2
应的正态密度曲线越瘦高;由决定系数和卡方独立性检验的定义和规则易知选项CD正确.故选ACD.
10【解析】对于选项A:因为 f(x2)是偶函数,所以 f(x2) f(x2),即 f(x)的图象关于直线x2对
称,所以选项A正确;对于选项B:由 f(x) f(x2)3得 f(x2) f(x4)3,所以 f(x) f(x4),
即4是函数 f(x)的一个周期,若6也为函数 f(x)的一个周期,则2为函数 f(x)的一个周期,那么
3
f(x) f(x2)32f(x),即 f(x) 为常数函数,不合题意,所以选项B错误;对于选项C:由A可知
2
新高考联考协作体 高二数学答案 第 1 页(共 6 页)
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f(1) f(3),对于 f(x) f(x2)3可令x1得 f(1) f(3)3,所以 f(1) ,所以选项C正确;
2
对于选项D:由A可得 f(x2) f(x2),求导可得 f '(2x) f '(2x)0即 f '(x) f '(4x)0,对
于 f(x) f(x2)3求导可得 f '(x) f '(x2)0,所以 f '(4x) f '(x2),即函数 f '(x)的图像关于直
线x3对称,所以选项D正确;故选ACD.
1 1 1 1
11【解析】对于选项A,将x等量替换为 ,则ln 1,所以lnx1 ,所以A正确;对于选项B,
x x x x
C0 C1 C6 1 1 1 1
6 6 6 (1 )6 ,因为ln(1 ) ,所以(1 )n e ,所以 B 正确;对于选项 C,因为
66 65 60 6 n n n
1 1 20241 2024 n1 n1
ln(1 ) ,所以 ln( )ln2025 ,所以 C 正确;对于选项 D,由 A 令 x 得
n n n n n
n1 n1
n1 n 1 2024 1 2024 n1
ln( )1 ,即 ln ln2025,所以D错误;故选ABC.
n n1 n1 n1 n
n1 n1
三、填空题:本题共3小题,每小题5分,共15分.
44 1 4
12. 13.(, ][3,) 14.( ,){0}
125 2 e2
2 2 3 2 44
12【解析】 p ( )2 C1 .
5 2 5 5 5 125
1 3 1 3
13【解析】x[ , ],当a0 时, f(x) x2 ax在[ , ]上单调递增;x[0,) ,当a 0 时,
2 2 2 2
x2 ax,0 xa 3 a 1 1
f(x) ,利用二次函数对称性可得 或a 即a3或0a .综上所述,a的取
x2 ax , xa 2 2 2 2
1
值范围是(, ][3,).
2
x x 1x
14【解析】设直线与曲线 y 的切点为(x ,y ),则切线方程为 y 1 1 (xx ),则过(0,t)的切线需
ex 1 1 ex 1 ex 1 1
x2 x2 x(2x)
满足:t 1 .令 f(x) ,则 f '(x) ,所以 f(x)在(,0)和(2,)单调递减,在(0,2)单调递
ex 1 ex ex
4
增,且当x时, f(x),当x时, f(x)0,而 f(0)0,所以t( ,){0}.
e2
四、解答题:本题共5小题,共77分.解答应写出文字说明、证明过程或验算步骤.
15.解:
(1)展开式所有项的二项式系数和为2n 512,所以n9,·······································3分
令 f(x)(12x)9,则所有项系数和为a a a f(1)(12)9 1;······················6分
0 1 10
b b Ck 2k Ck12k1
(2)由题意得a Cn(2)n,不妨令b |a |Cn2n,则 k k1 ,即 9 9 ,化简可得
n 9 n n 9 b
k
b
k1
C
9
k 2k C
9
k12k1
新高考联考协作体 高二数学答案 第 2 页(共 6 页)
{#{QQABLYAEogioAJIAAAgCAQG4CkKQkBGAAYgGxFAEsAIAQANABAA=}#}10k
21
k 17 20
解得 k ,因为kN,所以k 6········································10分
9k 3 3
1 2
k1
所以展开式中系数绝对值最大的项是第七项:C6(2x)6 5376x6.································13分
9
【备注】若最终式子均正确且结果算错,扣1分.
16.解:
(1)因为11.8,3.2,15,
1P( x)
所以旅游费用支出不低于1500元的概率为P(x) 0.15865,········4分
2
所以5000.1586579.325,
估计2023年有79.325万的游客在本市的年旅游费用支出不低于1500元.······························7分
(2)假设H :“客户星级”与“客户来源”独立,没有关联
0
客户星级
游客来源 合计
三星客户 一星客户
当地游客 200 400 600
····················10分
外地游客 100 300 400
合计 300 700 1000
100(0 200300100400)2
2 7.9376.635,···········································13分
400600300700
根据小概率值0.01的独立性检验,H 不成立,
0
即“客户星级”与“客户来源”有关联,此推断犯错误的概率不大于0.01.···························15分
【备注】根据评分细则酌情扣分.
17.解:
a1 a x2 axa1 (x1)[x(a1)]
(1) f '(x)1 ,x 1,x a1,·················2分
x2 x x2 x2 1 2
①当a10即a1时,易知 f(x)在(0,1)单调递减,在(1,)单调递增;······················3分
②当a11即a 2时, f '(x)0,则 f(x)在(0,)单调递增;·····························4分
③当0a11即1a2时,易知 f(x)在(0,a1)和(1,)单调递增,在(a1,1)单调递减;···5分
④当a11即a 2时,易知 f(x)在(0,1)和(a1,)单调递增,在(1,a1)单调递减;·········6分
综上所述:
新高考联考协作体 高二数学答案 第 3 页(共 6 页)
{#{QQABLYAEogioAJIAAAgCAQG4CkKQkBGAAYgGxFAEsAIAQANABAA=}#}当a1时, f(x)在(0,1)单调递减,在(1,)单调递增;
当a 2时, f(x)在(0,)单调递增;
当1a2时, f(x)在(0,a1)和(1,)单调递增,在(a1,1)单调递减;
当a 2时, f(x)在(0,1)和(a1,)单调递增,在(1,a1)单调递减;·························8分
(2)由(1)可知,只有当1a2和a 2时, f(x)才有极大值,
①当a 2时, f f(1)2a 3,解得a 5;······································10分
极大值
②当1a2时, f f(a1)a2aln(a1),
极大值
a 1
令g(a)a2aln(a1),则g'(a)1ln(a1) ln(a1) ,
a1 a1
1 1 2a
g''(a) 0,所以g'(a)在(1,2)单调递增,
a1 (a1)2 (a1)2
所以g'(a) g'(2)10,所以g(a)在(1,2)单调递减,
即g(a) g(2)0,所以g(a)3在(1,2)无解,故不存在符合题意的a;······················14分
综上所述:a 5·········································································15分
【备注】没有“综上所述”扣1分,过程不规范酌情扣分.
18.解:
记事件A :学生通过第i轮,事件B :学生通过第i轮就选择奖品离开,事件C :学生通过第i轮且继续答题,
i i i
1 1 2 1 1
(i 1,2,3).由题意得 P(A) , P(B | A) , P(C | A) , P(A |C ) , P(B | A ) ,
1 2 1 1 3 1 1 3 2 1 2 2 2 2
1 1
P(C | A ) ,P(A |C ) .
2 2 2 3 2 2
(1)记事件B:学生获得奖品. 则B B B B ,
1 2 3
1 1 1
P(B ) P(AB ) P(A)P(B | A) ···················································1分
1 1 1 1 1 1 2 3 6
1 2 1 1 1
P(B ) P(A)P(C | A)P(A |C )P(B |C ) ··································2分
2 1 1 1 2 1 2 2 2 3 2 2 12
1 2 1 1 1 1
P(B ) P(A)P(C | A)P(A |C )P(C | A )P(A |C ) ·····················4分
3 1 1 1 2 2 2 2 3 2 2 3 2 2 2 24
1 1 1 7
P(B) P(B )P(B )P(B ) ···············································6分
1 2 3 6 12 24 24
1 1
P(B B)P(B B) P(B )P(B ) 3
12 24
(2)P((B B )|B) 2 3 2 3 ;························9分
2 3 P(B) P(B) 7 7
24
1
(3)X 可取0, 1, 2, 3,P(X 0) P(A) ················································10分
1 2
新高考联考协作体 高二数学答案 第 4 页(共 6 页)
{#{QQABLYAEogioAJIAAAgCAQG4CkKQkBGAAYgGxFAEsAIAQANABAA=}#}P(X 1) P(AB C A ) P(AB )P(C A )
1 1 1 2 1 1 1 2
P(A)P(B | A)P(A)P(C | A)P(A |C )··········································12分
1 1 1 1 1 1 2 1
1 1 1 2 1 1
2 3 2 3 2 3
P(X 3) P(A)P(C | A)P(A |C )P(C | A )P(A |C )
1 1 1 2 1 2 2 3 2
1 2 1 1 1 1
·······································13分
2 3 2 2 2 24
1 1 1 1
P(X 2)1P(X 0)P(X 1)P(X 3)1 ······························15分
2 3 24 8
所以X 的分布列为:
X 0 1 2 3
1 1 1 1
P
2 3 8 24
1 1 1 1 17
E(X) 0 1 2 3 .······················································17分
2 3 8 24 24
【备注】解答没有用字母表示,只用数字计算,若结果正确不扣分,过程酌情扣分.
19.解:
(1)证明:因为 f(x)在[1,1]单调递增,x,x [1,1]且x x ,则| f(x ) f(x )| f(x ) f(x ),
i j i j j i j i
n n
所以| f(x ) f(x )|[f(x ) f(x )] f(x ) f(x ) f(1) f(1),
i i1 i i1 n 0
i1 i1
n
取M f(1) f(1),即可得| f(x ) f(x )| M ,所以 f(x)是[1,1]上的有界变差函数·········4分
i i1
i1
(2)x、x [1,1],且x x ,则| f(x ) f(x )||(x x )(x x )|2|x x |2(x x ),
i j i j j i j i j i j i j i
n n n
所以| f(x ) f(x )|2(x x )2[1(1)]4,取M 4,即可得| f(x ) f(x )| M ,
i i1 i i1 i i1
i1 i1 i1
所以 f(x)x2是定义在[1,1]上的有界变差函数··················································9分
1 1 1
(3)取x ,i 1,,n,其中x 0,则 f(x ) cos(ni1)(1)ni1 ,
i ni1 0 i ni1 ni1
1 1 1 1
所以当i2时,| f(x ) f(x )||(1)ni1 (1)ni2 | ,
i i1 ni1 ni2 ni1 ni2
n n 1 1 1 n 1 1 n 1
| f(x ) f(x )|| f(x ) f(0)|( ) ( )2 1·········13分
i i1 1 ni1 ni2 n i1 i i
i1 i2 i2 i1
n 1
下证2 1无界:
i
i1
x1
令h(x) xlnx1,h'(x) ,h(x)在(0,1)单调递减,在(1,)单调递增,所以h(x)h(1)0,
x
新高考联考协作体 高二数学答案 第 5 页(共 6 页)
{#{QQABLYAEogioAJIAAAgCAQG4CkKQkBGAAYgGxFAEsAIAQANABAA=}#}n1 n1 1 n 1 n i1
即x1lnx,取x ,即可得ln ,所以2 2ln 2ln(n1),
n n n i i
i1 i1
n 1 n 1
那么2 12ln(n1)1,易知当n时,2ln(n1)1,所以2 1无界·········16分
i i
i1 i1
n
所以不存在常数M 0使得| f(x ) f(x )| M ,因此 f(x)在[0,1]不是有界变差函数.···········17分
i i1
i1
【备注】解答过程根据评分细则酌情扣分.
新高考联考协作体 高二数学答案 第 6 页(共 6 页)
{#{QQABLYAEogioAJIAAAgCAQG4CkKQkBGAAYgGxFAEsAIAQANABAA=}#}