2024~2025学年度第一学期期末学业水平诊断
高二数学
注意事项:
1.本试题满分150分,考试时间为120分钟。
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一、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
符合题目要求。
11.11
1.若一数列的前4项分别为
35'79
则该数列的通项公式可能为
A.a,-)*1
C.a--
D.a=
(-1)”
2n+1
B.a=(-1)"
2n+1
2n-1
2n-1
2.已知精二+上=1一个熊点的坐标为0,,则m的值为
2
m
A.1
B.3
C.4
D.5
3.已知等差数列{an}的前n项和为Sn,且a6+a=8,则S3=
A.52
B.104
C.112
D.120
4已知R,5分别为椭圆C:父+
=1的左、右焦点,直线y=2x与C交于两点A,B,则
84
平行四边形AFBF的周长为
A.4W2
B.8
c.82
D.16
5.某隧道的垂直剖面图近似为一抛物线,如右图所示.已知隧道
高为6m,宽为8m,隧道内设置两条车道,且隧道内行车不
6m
准跨过中间的实线,若载有集装箱的货车要经过此隧道,货车
宽度为2m,集装箱宽度与货车宽度相同,则货车高度(即集
装箱最高点距地面的距离)的最大值为
8m-
A.3.5m
B.4m
c.4.5m
D.5m
6.设[x]和{x}分别表示正实数x的整数部分、小数部分,例如[1.2]=1,{1.2}=0.2.已知
数列a,}满足g=2+V2,a=[a,1+
n∈N,则a2o2s5=
a.}
A.2025+V2
B.2026+V2
·C.4050+√2
D.4052+V2
高二数学试题(第1页,共4页)
7若过点(-30)的直线1与双自战号-芳=a>0>0知交于人8两点,且AB关于直
线x+y-5=0对称,则该双曲线的渐近线方程为
A.y=±3x
B.y=±2x
C.y=tv3x
D.y=tv2x
8.已知等差数列{o,}的前n项和S,=n2,数列,}的前n项和为了,且6,=(-1)”_”,
aranti
若不等式T,≤入(n∈N)恒成立,则实数元的最小值为
B.-1
c-i
D.-5
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.在平面直角坐标系xOy中,若一曲线的方程为(1-2)x2+2y2=1,则
A.当0<入<1时,该曲线为椭圆
B.当九<0时,该曲线为焦点在x轴上的双曲线
C.当2>1时,该曲线为焦点在y轴上的双曲线
D.无论1取何值,该曲线不可能为等轴双曲线
已知数列{0,}的前n项和为S,且满足a,+24,++2a,=”2”(1eN),
A.a=1
B.a=
2n
C{a,}为递减数列D.了=4-n+3
2
11.已知P为抛物线C:x2=4y上一点,F为C的焦点,直线1的方程为3x+4y+6=0,
则下列说法正确的有
A.若A(3,4),则川AP|+|PF25
B.点P到直线!的距离的最小值为
33
C.点P到直线1与到直线y=-2的距离之和的最小值为2
D.若存在点P,使得过点P可作两条垂直的直线与圆x2+(y-4)2=r2相切,则r的取值
范围为r≥√6
三、填空题:本题共3小题,每小题5分,共15分。
12.在平面直角坐标系xOy中,到y轴的距离与到点(2,0)的距离相等的点的轨迹方程
为
高二数学试题(第2页,共4页)2024~2025 学年度第一学期期末学业水平诊断
高二数学参考答案
一、选择题
1.A 2.B 3. A 4.C 5.C 6.C 7.B 8.D
二、选择题
9.BCD 10.AD 11.ABD
三、填空题
y2 4x 4 0 4 2 , 10 12. + = 13. 14. 2 6
四、解答题
15.解:(1)因为a5 a6 = a2 a17 ,所以 (a1 + 4d )(a1 + 5d ) = (a1 + d )(a1 +16d ).
2
整理得d = 2a1d ,又数列{an}的公差为d ≠ 0,所以d = 2a1 . ··············· 2分
S S 16 (5a 5×4 d ) (3a 3×2又 5 3 = ,所以 1 + 1 + d ) =16 , 2 2
即 2a1 + 7d =16, ·································· 4分
联立上述两个方程,解得a1 =1, d = 2 ,所以an = 2n 1. ························ 6分
b = 2n(2) n (2n 2) = (n 1)2
n+1
, ························ 7分
T 2 3n = 0×2 +1×2 + + (n 2)×2
n + (n 1)×2n+1,
2Tn = 0×2
3 +1×24 + + (n 2)×2n+1 + (n 1)×2n+2 . ························ 9分
T = 23 + 24 + + 2n+1 (n 1)2n+2两式相减得 n ,
8(1 2n 1)
= (n 1) 2n+2 = (2 n) 2n+2 8, ······················· 12分
1 2
所以T = (n 2) 2n+2n +8 . ······················· 13分
16.解:(1)设点 P(x0,4) | PF | x
p 5p
,则 = 0 + = ,所以 x = 2 p . ··················· 2分 2 2 0
将 P(2 p,4)代入C : y2 = 2 px( p > 0),可得 p = 2 , ································· 4分
所以抛物线的标准方程为 y2 = 4x ; ······························· 5分
(2)抛物线的焦点 F (1,0) ,设直线 l的方程为 x = my +1, A(x1, y1), B(x2, y2 ) ,
因为 AF = 3FB,所以 y1 = 3y2 . ··················································· 7分
x = my +1
联立 2 ,得 y
2 4my 4 = 0, ·················································· 9分
y = 4x
所以 y1 + y2 = 2y2 = 4m,即 y2 = 2m ,
又 y1 y
2
2 = 3y2 = 4,所以 3( 2m)
2 4 2 1= ,解得m = . ······················· 12分
3
所以 | AB |= x1 + x2 + p = m(y1 + y2 ) + 4 = 4m
2 16+ 4 = . ························· 15分
3
高二数学答案(第 1 页,共 4 页)
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17.解:(1)由题意可知,c = 1, a + c = 3,所以a = 2 . ··················· 2分
x2 y2
又b2 = a2 c2 = 4 1 = 3,所以椭圆C 的方程为 + = 1; ················· 4分
4 3
(2)(i)设过点 F (1,0) 的直线方程为 x = my +1,点M (x1, y1), N (x2, y2 ) ,
x2 y2
+ =1
联立 4 3 ,得 (3m2 + 4)y2 + 6my 9 = 0,
x = my +1
则 y1 + y
6m 9
2 = 2 , y1y2 = 2 , ························· 5 分 3m +4 3m +4
2
则 | MN |= 1+m2 (y y )2 4y y 12(m +1)1 + 2 1 2 = . ·························· 6分 3m2 + 4
3
又因为点 A( 2,0) 到直线 l的距离d = . ·························· 2 7分 1+m
1 18 1+m2 6
令 S = | MN | d = = 15 ,解得m = ± , ··························· 9分
2 3m2 + 4 3
所以,直线 l的方程为3x ± 6y 3 = 0 . ·························· 10分
y1 y2
(ii)因为直线 BM : y = (x 2),直线 AN : y = (x + 2) , ····· x1 2 x2 + 2
11分
x + 2 (x2 + 2)y1 = my y= 1 2 + 3y1所以 ·········································· x 2 (x1 2)y2 my1y
. 12分
2 y2
9 3
3 x + 2 my y1 + y2
因为my y = (y + y ) ,所以 = 1
y2 + 3y1
1 2 1 2 =
2 2
3 1 = 3, ····· 14分 2 x 2 my1y2 y2 y1 + y2 2 2
x + 2
即 = 3,解得 x = 4,所以点 P 在直线 x = 4上. ························· 15分
x 2
18.解:(1)由题意c = 2a ,b2 = c2 a2 = 3a2 . ································ 2分
4 9
将点 (2,3)代入双曲线方程得 =1,解得a2 2
a2 2
=1,b = 3 .
b
y2
所以,双曲线的方程为 x2 =1; ···································· 4分
3
(2)(i)设点 A(x1, y1), B(x2 , y2 ),直线方程为 x = my + 2,
2
x2
y
=1
联立方程 3 ,得 (3m2 1)y2 +12my + 9 = 0 , ························ 6分
x = my + 2
12m 9
所以 y1 + y2 = 3m2
, y1 y2 = 2 , 1 3m 1
x x m(y y ) 4 4 x x 3m
2 4
1 + 2 = 1 + 2 + = 2 , 1 2 = 2 . ························ 8分 3m 1 3m 1
高二数学答案(第 2 页,共 4 页)
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设M (s, t) ,则MA MB = (x1 s, y1 t) (x2 s, y2 t)
= x1x2 s(x1 + x2 ) + y1 y2 t(y
2 2
1 + y2 ) + s + t =0 , ·································· 9分
即 ( 3+ 3s2 + 3t 2 )m2 +12tm + 4s + 5 (s2 + t 2 ) = 0 对任意m 恒成立.
所以 3+ 3s2 + 3t 2 =0,12t=0,4s + 5 (s2 + t 2 )=0 ,解得 s = 1, t = 0 ········· 11分
所以,以 AB 为直径的圆恒过点M ( 1,0) . ································ 12分
2
| AB | 1 m2 | y 6(m +1)(ii) = + 1 y2 |= 2 . ··································· 13分 3m 1
y y1 + y2 6m x 3m
2 +1
由题意可知 N = = 2 ,代入双曲线方程可得 N = 2 , ·· 14分 2 3m 1 3m 1
设 AB 的中点为 E ,则
3m2| NE | | x +1 x + x 3m
2 +1 1 4 3m2 + 3
= N xE |= 1 2 = × = , ···· 15 分 3m2 1 2 3m2 1 2 3m2 1 3m2 1
1
所以 | NE |= | AB |,所以∠ANB = 90 .
2
又∠AMB = 90 ,所以 A, B, N , M 四点共圆. ··································· 16分
由相交弦定理得 | AP | | PB |=| MP | | PN | . ································· 17分
19.解:(1)当n ≥ 2 时,2Sn 1 = nan 1 , ···························· 1分
a n
两式相减得2an = (n +1)a
n
n nan 1,即 =a n 1 . ············ 2分 n 1
a an an 1 a2 n n 1 2累乘得 n = × × × ×a1 = × × × ×2 = 2nan 1 an 2 a1 n
. ········· 4分
1 n 2 1
经检验a1 = 2也符合上式,所以an = 2n . ··········································· 5分
2
(2)因为bn = ,所以b
2 1 1 1 1
n = = = ( ), ······· 6分 anan+1 2n×2(n +1) 2n(n +1) 2 n n +1
M 1 1 1 1 1 1 1 1所以 n = [(1 ) + ( ) + + ( )] = (1 ), ·················· 7分 2 2 2 3 n n +1 2 n +1
假设存在正整数m,n(2 < m < n),使得M 2 , M m , M n 成等差数列,则M 2 + M n = 2M m ,
2 1 1 18
即 = + ,即m = 5 , ··········································· 8分
m +1 3 n +1 n + 4
显然n + 4 是18的正约数,又因为n > m > 2 ,所以n + 4 > 6,所以n + 4 = 9或18,
当 n + 4 = 9,即n = 5时,m = 3,
当 n + 4 =18,即n =14 时,m = 4 . ······································· 10分
所以,存在正整数m,n( 2 < m < n),使得 M 2 , M m , M n 成等差数列,
此时m = 3,n = 5或m = 4, n =14 . ······································· 11分
高二数学答案(第 3 页,共 4 页)
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n
(3)由题意知,cn = 2 1, ········································· 12分
2
当 n =1时, 2 = 2 < 3c ,不等式成立. ················································ 13分 1
2n 2n 2n 2n 1
当 n ≥ 2 ,因为 = < =
c2 nn (2 1)
2 (2n 1)(2n 2) (2n 1)(2n 1 1)
1 1
=
2n 1
n , ········································· 15分 1 2 1
n
∑ 2
i
2 1 1 1 1 1 1所以 2 = + ( +c 21 1 22 1 22
3 + + )
i=1 i 1 2 1 2
n 1 1 2n 1
2 1= + (1 n )
1
= 3 n . ······························ 16分 2 1 2 1
1 1
因为2n 1> 0,所以 n > 0,3 n < 3, 2 1 2 1
n 2i
所以n ≥ 2时,∑ 2 < 3,
i=1 ci
n 2i
综上,∑ 2 < 3 . ····························· 17分
i=1 ci
高二数学答案(第 4 页,共 4 页)
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