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内江市 2023 ~ 2024 学年度第一学期高二期末检测题
数学参考答案及评分意见
一、单项选择题:(本大题共8个小题,每小题5分,共40分.)
1. C 2. B 3. C 4. A 5. D 6. D 7. B 8. A
二、多项选择题:(本大题共4个小题,每小题5分,共20分.全部选对得5分,部分选对得
2分,选错得0分.)
9. ABC 10. BD 11. AC 12. BC
三、填空题:(本大题共4小题,每小题5分,共20分.)
13. 2n + 1 14. 3槡510 a 15.①椭圆 ② > 16.(槡
6
2 ,槡3]
解答题(本大题共6小题,共70分.)
17.解:(1)线段AB的垂直平分线方程为y = - x + 3 2分
!!!!!!!!!!!!!
与x - y - 1 = 0联立得,x = 2,y = 1,即圆心C(2,1),
所以圆C的半径R = |AC | = 2槡2 4分!!!!!!!!!!!!!!!!!!!!!
所以,圆C的标准方程为(x - 2)2 +(y - 1)2 = 8 5分
!!!!!!!!!!!!!!!
(2)∵ |CP | = |CQ | = 2槡2,CP⊥CQ,∴圆心C到直线m的距离d = 2. 6分!!!!!!
当直线m的斜率存在时,设直线m的方程为y = k(x - 4).
由d = |2k + 1 |得k = 34 8分!!!!!!!!!!!!!!!!!!!!!!!!!槡k2 + 1
当直线m的斜率不存在时,直线m方程为x = 4,C到m距离为2, 9分
!!!!!!!
综上可得,直线m方程为3x - 4y - 12 = 0或x - 4 = 0 10分
!!!!!!!!!!!!
18.解:(1).数列{an}是等比数列.理由如下: 1分!!!!!!!!!!!!!!!!
由Sn - an + 1 + 2 = 0,得Sn = an + 1 - 2 ①
则当n≥2时,Sn - 1 = an - 2 ②
① -②得Sn - Sn - 1 = an + 1 - an.所以an = an + 1 - an,即an + 1 = 2an 4分!!!!!!!!
又因为a1 = 2,且a2 = a1 + 2 = 4,所以{an}是公比为2的等比数列.所以an = 2n 6分!!
(2)证明:由(1)知bn = log22n = n, 7分!!!!!!!!!!!!!!!!!!!!!
则1 = 1 1 1 1bnbn + 2 n(n + 2)= 2 (n - n + 2) 9分!!!!!!!!!!!!!!!!!!!!
所以Tn = 12 [(1 -
1 )+(1 1 1 1 1 13 2 - 4 )+(3 - 5 )+…+(n - n + 2)]
= 1 (1 + 1 - 1 1 3 12 2 n + 1 - n + 2)= 4 - 2 (
1
n + 1 +
1 3
n + 2)< 4 12分!!!!!!!
19.解:(1)因为直三棱柱ABC - A1B1C1,所以AA1⊥平面ABC,
因为CD?平面ABC,所以AA1⊥CD; 2分!!!!!!!!!!!!!!!!!!!!
因为△ABC是等边三角形,D是棱AB的中点,所以CD⊥AB; 3分!!!!!!!!!
因为AB、AA1?平面ABB1A1,且AB∩AA1 = A,所以CD⊥平面ABB1A1, 4分!!!!!!
因为CD?平面A1CD,所以平面A1CD⊥平面ABB1A1 5分!!!!!!!!!!!!!
(2)分别取AC、A1C1的中点为O、E,连接OB、OE,因为△ABC是等边三角形,O是AC中
高二数学试题答案第 1页(共4页)
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点,所以OB⊥OC,因为直三棱柱ABC - A1B1C1,
所以AA1⊥平面ABC,因为OB、OC?平面ABC,
所以AA1⊥OB,AA1⊥OC,
因为O、E为AC、A1C1的中点,所以OE∥AA1,
所以OE⊥OB、OE⊥OC,即OB、OC、OE两两垂直, 6分!!!!!
以{?O→B,?O→C,?O→E}为正交基底建立如图所示的空间直角坐标系,
!
7分
!!!!!!!!!!!!!!!!!!!!!!!!!!
则A1(0,- 1,2),C(0,1,0),D(槡32 ,-
1
2 ,0),
所以?A→1C =(0,2,- 2),?C→D =(槡32 ,-
3
2 ,0) 8分!!!!!!!!!!!!!!!!!!
珗n·?A→1C = 2y - 2z = 0
设平面A1CD的法向量为珗n =(x,y,z),所以{珗n·?C→ ,D =槡32 x - 32 y = 0
取y = 1,则珗n =(槡3,1,1), 9分!!!!!!!!!!!!!!!!!!!!!!!!
平面ACC1A1的一个法向量为m珝=(1,0,0); 10分!!!!!!!!!!!!!!!!
则| cos〈m珝,珗n〉 珝 珗| = |m·n | 槡3 槡15|m珝|·|珗n | = = 5 , 11分!!!!!!!!!!!!!!!!!!槡5
所以锐二面角D - A C - A的余弦值为槡151 5 12分!!!!!!!!!!!!!!!!
20.解:(1)若选①S4 = 15,S2 = 3:设{an}公比为q(q > 0),显然q≠1.
a (1 - q4由 1 ) a1(1 - q
2)
S 1 - q
4
4 = 1 - q = 15,S2 = 1 - q = 3,两式作商可得 2 = 5, 2分!!!!!!!1 - q
整理得q2 = 4,解得q = 2或q = - 2(舍去), 4分
!!!!!!!!!!!!!!!!!
将 a (1 - q
2)
q = 2代入S2 = 1 1 - q = 3可得a1 = 1,所以an = a q
n - 1
1 = 2
n - 1; 6分
!!!!!!
若选②a1 + a2 = 3,a3 = 4:设{an}公比为q(q > 0),显然q≠1.由a1 + a2 = a1(1 + q)= 3,
2
a3 = a1q
2 = 4,两式作商可得q = 41 + q 3 , 2分!!!!!!!!!!!!!!!!!!!!!
整理得3q2 - 4q - 4 = 0,解得q = 2或q = - 23 (舍去), 4分!!!!!!!!!!!!
将q = 2代入a3 = a 21q = 4可得a1 = 1, 4分!!!!!!!!!!!!!!!!!!!
所以an = a n - 11q = 2n - 1 6分!!!!!!!!!!!!!!!!!!!!!!!!!!
(2)由(1)知,a = 2n - 1n ,
则n = n ,所以T = 1 + 2 + 3 na n - 1 n 0 1 2 +…+ n - 1, 8分!!!!!!!!!!!!!!!!n 2 2 2 2 2
1 T = 1 + 2 + 3 +…+ n2 n 1 2 3 n两式相减,则2 2 2 2
1
0[1 -(1 )n]1 T = 1 + 1 + 1 +…+ 1 - n = 2 2 - n = 2 -(1 )n - 1 n2 n 20 21 22 2n - 1 2n 1 2n 2 - 2n, 11分!!1 - 2
高二数学试题答案第 2页(共4页)
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所以T = 4 -(1 )n - 2 - n = 4 -(n + 2)(1 )n - 1n 2 n - 1 2 12分!!!!!!!!!!!!!!2
21.解:(1)取AD的中点O,连接OP、OB,如图.
因为PA = PD,所以OP⊥AD.
因为平面PAD⊥平面ABCD且平面PAD∩平面ABCD = AD,
OP?平面PAD,
所以OP⊥平面ABCD.
因为OB?平面ABCD,所以OP⊥OB.
在菱形ABCD中,∠BAD = 60°,
所以△ABD是等边三角形,所以OB⊥AD 2分!!!!!!!!!!!!!!!!!!
所以OA、OB、OP两两相互垂直,由此建立空间直角坐标系,
则P(0,0,2),A(1,0,0),B(0,槡3,0),C(- 2,槡3,0),D(- 1,0,0), 3分!!!!!!!
所以?A→P =(- 1,0,2),?D→P =(1,0,2),?P→C =(- 2,槡3,- 2).
所以?D→M = ?D→P + ?P→M = ?D→P + 3 ?P→4 C =(1,0,2)+
3
4 (- 2,槡3,- 2)
=(- 1 ,3槡3,12 4 2 ). 5分!!!!!!!!!!!!!!!!!!!!!!!
设直线AP与DM所成的角为θ,
?→ ?→ 1 + 1
则cosθ = AP·DM?→ ?→ = 2 6槡7|AP | |DM | = 35 6分!!!!!!!!!!!!!
槡5 ×槡1 + 27 + 14 16 4
(2)由(1)知?A→P =(- 1,0,2),?P→B =(0,槡3,- 2),?D→M =(- 1 ,3槡3,1 ),?D→2 4 2 B =(1,槡3,0).
设平面BDM的法向量为珗n =(x,y,z),
{珗n·?D→M = - 1 x + 3槡3 1则 2 4 y + 2 z = 0珗n·?D→B = x +槡3y = 0
取y = 2槡3,得珗n =(- 6,2槡3,- 15) 8分!!!!!!!!!!!!!!!!!!!!
设PNPB = λ,则
?P→N = λ ?P→B(0 < λ < 1),
所以?A→N = ?A→P + ?P→N = ?A→P + λ ?P→B =(- 1,0,2)+ λ(0,槡3,- 2)
=(- 1,槡3λ,2 - 2λ) 10分!!!!!!!!!!!!!!!!!!!!!!!
若AN∥平面BDM,则?A→N·珗n = 6 + 6λ - 15(2 - 2λ)= - 24 + 36λ = 0,解得λ = 23 ,
所以在棱PB上存在点N,使AN∥平面BDM,此时PN = 2PB 3 12分!!!!!!!!!!
22.解:(1)由题意知|AB | = 2a = 4,a = 2,又离心率e = c = 1a 2 ,即c = 1,
x2 2∴ b2 = a2 - c2 = 3,椭圆C的方程为 + y4 3 = 1 3分!!!!!!!!!!!!!!!!
高二数学试题答案第 3页(共4页)
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2 2
(2)∵ F(1,0),设MN的方程为x = y + 1带入x + y4 3 = 1有:
3(y + 1)2 + 4y2 - 12 = 0,即7y2 + 6y - 9 = 0 4分
!!!!!!!!!!!!!!!!!
设M(x1,y 6 91)、N(x2,y2),则y1 + y2 = - 7 ,y1y2 = - 7
∴ | y1 - y2 | =槡(y1 + y )22 - 4y1y =槡(- 6 )2 + 4 × 9 = 12槡22 7 7 7 5分!!!!!!!!!
∴ S 1 1 12槡2 18槡2△AMN = 2 AF·| y1 - y2 | = 2 × 3 × 7 = 7 7分!!!!!!!!!!!!!!
(3)由(1)得A(- 2,0),B(2,0),
设P(m,n),则3m2 + 4n2 = 12,即4n2 = 12 - 3m2;
直线PA:y = nm + 2(x + 2),直线PB:y =
n
m - 2(x - 2),
∴ D点纵坐标y = 6nD m + 2,E点纵坐标y =
2n
E m - 2,
即D(4,6nm + 2),E(4,
2n
m - 2), 9分!!!!!!!!!!!!!!!!!!!!!!!
∴以DE为直径的圆的方程为:(x - 4)(x - 4)+(y - 2nm - 2)(y -
6n
m + 2)= 0 10分!!!
由对称性可知:以DE为直径的圆所过定点位于x轴上,
设y = 0,∴ (x - 4)2 + 2n 6nm - 2 × m + 2 = 0
2 2
∴ (x - 4)2 + 12n2 = 0,∴ (x - 4)2 + 36 - 9mm - 4 m2 = 0- 4
∴ (x - 4)2 = 9,解得x = 1或x = 7
∴以DE为直径的圆过点(1,0),(7,0) 12分
!!!!!!!!!!!!!!!!!!
高二数学试题答案第 4页(共4页)
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