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参考答案
题号 1 2 3 4 5 6 7 8
答案 C D D B D B A A
题号 9 10 11
答案 ABD BC ACD
12. 5 13.12 14.2022
4.【详解】奇函数图像关于原点对称,所以在关于原点对称区域内单调性相同,函数y f(x)是奇函数且
在区间5,1上单调递增,则函数y f(x)在区间1,5上单调递增,由于区间为半开半闭区间,所以存
在最大值.故选B.
1
2r 2r
S 3 2
2
5.【详解】设圆锥底面半径为r,则高也为r, 6,所以r 3,母线长为
V 1 r
r2r
3
2r 6.故选D
6.【详解】由题可先将1号球分给甲,再将情况进行分类:
第一类,甲只有一个球,则另外三个球分给乙和丙两位同学,有C2A2 =6种方法,
3 2
第二类,甲有两个球,则需要将3个球分发给3位同学的方法数有A3 6种,
3
所以共有6+6=12种分法.故选B.
7.【详解】随机变量X 的密度曲线关于x2对称,
PX 0PX 3 PX 4PX 3 PX 4PX 4P3 X 4
13 1
1P3 X 4 ,所以P3 X 4 .故选A
12 12
8.【详解】设a ,a ,a ,a 平均数为a,因为s2 1 4 a2 a 2 ,得a 2 25,由a0,故a5.则
1 2 3 4 4 i
i1
样本数据4a 1,4a 1,4a 1,4a 1的平均数为4a121.故选A
1 2 3 4
2
P(B A )
11.【详解】由题意可知P(A)P(A )P(A ) 1 ,P(B A) 4 ,P(C A) 1 , 2 5 ,A正确,B
1 2 3 3 1 5 1 5
11
错误;P(B A ) 1,P(B)P(A)P(B A)P(A )P(B A )P(A )P(B A ) ,C正确;
3 1 1 2 2 3 3 15
1 4
P(AB) 3 5 4
P(A B) 1 ,D正确;故选ACD.
1 P(B) 11 11
15
14.【详解】 f x21为奇函数,所以 f x关于点2,1对称, f 2x1为偶函数,所以 f x关于直线
x1对称,故 f x的周期为4, f 2 f41, f 1 f32, f 2025 f12
2025
所以 f(i)506(f(1) f(2) f(3) f(4)) f(2025)506422022 ,故答案为2022.
i1
15.(本小题满分13分)
(1)由S 25可得a 5,·····························································································2分
5 3
由a a a a 12可得d 2,····················································································4分
2 5 3 4
故a 2n1.·················································································································6分
n
(2) 由(1)得S n2,································································································8分
n
高二数学 第 1 页 共 4 页
{#{QQABTQYg4gi4wBbACY4LUQU4CwoQsJMjLcokwQASKAQKCRFABKA=}#}1 1 1 1 1 1
故b ( )··············································11分
n 4S 1 4n21 (2n1)(2n1) 2 2n1 2n1
n
1 1 1 1 1 1 n
则T (1 ) .··························································13分
n 2 3 3 5 2n1 2n1 2n1
16.(本小题满分15分)
a
解:(1) fx2x2a1 , f11a 3,所以a 2·············································2分
x
f x x2 3x2lnx , f 14,切点为1,4 ··································································4分
切线方程为 y43x1,即3x y10········································································6分
lnx
(2)x2 xlnxmx ,x0,m x1 ··························································8分
x
min
lnx x2 1lnx
设gx x1 ,x0,,gx ·························································9分
x x2
2x2 1
设hx x2 1lnx,x0,,hx 0,hx在0,上单调递增············11分
x
h10,x0,1时hx0即gx0,gx在0,1上单调递减
x1,时hx0即gx0,gx在1,上单调递增············································13分
gx g1 2,m2························································································15分
min
17.(本小题满分15分)
答:(1)由频率分布直方图可知,0.004a0.0180.0220.0220.028101,解得a0.006,···2分
该校学生满意度打分不低于70分的人数为:10000.280.220.18680.··································4分
(2)平均数为:x450.04550.06650.22750.28850.22950.1876.2;················6分
所以0.040.060.220.280.6,0.040.060.220.280.220.82,
0.750.6
所以75%的分位数为80 1086.82 .······································································8分
0.820.6
(3)由频率分布直方图可知,打分在60,80和80,100内的频率分别为0.5和0.4,
所以打分在60,80和80,100内的频率之比为5:4,·································································9分
5
所以在打分60,80中抽取的人数为 95人;
9
4
在打分80,100中抽取的人数为 94人.···········································································11分
9
设“至少有一份答卷成绩为优秀”为事件A,···········································································12分
C1C1C2C0 13 13
则P(A) 4 5 4 5 .至少有一份答卷成绩为优秀 .······················································15分
C2 18 18
9
18.(本小题满分17分)
【解】(1)因为 f xex,则 fxex,fxex,·····························································1分
f0
1 2
K
所以
1f0
2 3
2
112 3
2
4 .················································································3分
(2)因为 f xex,则 fxex, fxex ,
fx ex
K
所以 3 3 ,····················································································4分
1fx
2
2
1e2x
2
高二数学 第 2 页 共 4 页
{#{QQABTQYg4gi4wBbACY4LUQU4CwoQsJMjLcokwQASKAQKCRFABKA=}#}t
g(t)
令t ex(t 0), 3
1t2
2
3 3 1
1t2
2t
1t2
22t
则gt 2
1t23t2
12t2
,·························································6分
1t23
1t2
5
2
1t2
5
2
当0t 2 时,g't0,gt单调递增,
2
当t 2 时,g't0,gt单调递减,···············································································8分
2
所以gt g 2 2 3 ,所以曲率K最大值为 2 3 .··························································9分
max 2 9 9
1 32m 1 1
(3)h(x)(x2)ex x3( )x2 x2lnx,h(x)(x1)ex x2(1m)xxlnx
6 4 2 2
h(x)xexxlnxm·····································································································10分
因为hx不存在曲率为0的点,所以hx0在(0,)无实数解,令t(x)xexxlnx
1 xex x2ex x1 (xex 1)(x1)
t(x)exxex1 ,··························································12分
x x x
令(x)xex1,x0 ,求导得(x)ex(x1)0,函数(x)在(0,)上单调递增,
1 1 1 1
而( ) e10,(1)e10,则存在x ( ,1),使(x )0,即t(x )0,此时ex0 ,
2 2 0 2 0 0 x
0
当x(0,x )时,t(x)0;当x(x ,) 时,t(x)0,
0 0
函数t(x)在(0,x )上单调递减,在(x ,)上单调递增,····························································15分
0 0
1
因此t(x) t(x ) x ex0 x lnx ,由ex0 ,得x lnx ,
min 0 0 0 0 x 0 0
0
则t(x )1x x 1,m1,所以m的取值范围是(,1).·····················································17分
0 0 0
19.(本小题满分17分)
(1)记选择方案二学生的得分为X
P(X 100)(p p )2······································································································1分
0 1
(p p )2 1 1
p p 0 1 ,当且仅当 p p 时取等,························································2分
0 1 4 4 0 1 2
1
此时满分概率为 ···········································································································3分
16
(2)在方案一中,记A类题得分为Y ,B类题得分为Y ,选择方案一学生得分为Z
1 2
1 1 1 1 7
P(Y 50) ,P(Y 0)1
1 2 4 8 1 8 8
1 1 1 1 1 1 1 1 1
P(Y 0) ,P(Y 25)C1 ,P(Y 50)
2 2 2 4 2 2 2 2 2 2 2 2 4
由题可知Z 可能的取值为0、25、50、75、100
7 1 7 7 1 7 7 1 1 1 1
P(Z 0) ,P(Z 25) ,P(Z 50) ,
8 4 32 8 2 16 8 4 8 4 4
1 1 1 1 1 1
P(Z 75) ,P(Z 100) ·································································7分
8 2 16 8 4 32
高二数学 第 3 页 共 4 页
{#{QQABTQYg4gi4wBbACY4LUQU4CwoQsJMjLcokwQASKAQKCRFABKA=}#}Z 的分布列为
Z 0 25 50 75 100
···················································································8分
7 7 1 1 1
P
32 16 4 16 32
(3)方法一:
记A、B类题得分分别为事件A、B,当A类题只需答对一道得50分为事件A'
1
由2p q 1(p q )可得0 p ··············································································9分
0 0 0 0 0 3
E(Z)E(A2B)E(A)2E(B),E(X)E(A)E(A')
故E(Z)E(X)2E(B)E(A')······················································································11分
E(B)25q 0(1q )25q
0 0 0
E(A')501(1 p )(1 p )0(1 p )(1 p )5012(1 p )p q ·································13分
0 1 0 1 0 0 0
所以E(Z)E(X)2E(B)E(A')50q 50100(1 p )p q
0 0 0 0
50(12p )50100(1 p )p (12p )100(1 p )p (12p )100p
0 0 0 0 0 0 0 0
100p (1 p )(12p )1100p 2(2p 3)0
0 0 0 0 0
所以E(Z)E(X)应选择方案二·······················································································17分
方法二:
1
由2p q 1(p q )可得0 p ··············································································9分
0 0 0 0 0 3
若选择方案一,学生得分Z 可能的取值分别是0、25、50、75、100
P(Z 0)(1 p p )(1q )2,P(Z 25)(1 p p )C1q (1q ) ,
0 1 0 0 1 2 0 0
P(Z 50) p p (1q )2(1 p p )q 2,P(Z 75) p pC1q (1q )
0 1 0 0 1 0 0 1 2 0 0
P(Z 100) p pq 2,所以E(Z)50q 50p p ································································11分
0 1 0 0 0 1
若选择方案二,学生得分X 可能的取值分别是0、50、100
P(X 50) p p (1 p )(1 p )(1 p p )1(1 p )(1 p ) ,
0 1 0 1 0 1 0 1
P(X 100) p p 1(1 p )(1 p ) ,
0 1 0 1
所以E(X)5050p p 50(1 p )(1 p ) ······································································13分
0 1 0 1
所以E(Z)E(X)50q 5050(1 p )(1 p )50q 50100(1 p )p q
0 0 1 0 0 0 0
50(12p )50100(1 p )p (12p )100(1 p )p (12p )100p
0 0 0 0 0 0 0 0
100p (1 p )(12p )1100p 2(2p 3)0
0 0 0 0 0
所以E(Z)E(X)应选择方案二·······················································································17分
高二数学 第 4 页 共 4 页
{#{QQABTQYg4gi4wBbACY4LUQU4CwoQsJMjLcokwQASKAQKCRFABKA=}#}