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中学生标准学术能力诊断性测试 2024年 3月测试
数学参考答案
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 2 3 4 5 6 7 8
D C B D A C B C
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,部分选对但不全的得2分,有错选的得0分.
9 10 11 12
CD ABD BCD ABD
三、填空题:本题共4小题,每小题5分,共20分.
185
13.16
14.−
8
15. 645 16.a+b
451
四、解答题:本题共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.(10分)
2tanC 3
(1) tan2C = =− ········································································· 2分
1−tan2C 4
10
解得tanC=3,故cosC = ·································································· 4分
10
10
(2) a2 +b2 =c2 +2abcosC =16+ ab2ab ·············································· 6分
5
80+8 10
解得ab ·················································································· 8分
9
3
由(1)知sinC =
10
1 4+4 10
故S = absinC ································································ 10分
ABC 2 3
4+4 10
故ABC面积的最大值为 .
3
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{#{QQABbYAEggCAQBIAAQhCAwGYCAGQkACCCKoOABAEsAAAyRNABCA=}#}18.(12分)
(1)对于n2时,a +4(n+1)=2a +8n=2(a +4n) ······································ 2分
n+1 n n
a =2,a +41=6,
1 1
a +4n=32n,a =32n −4n ··································································· 3分
n n
经验算,a 符合上述结果,故a =32n −4n ················································· 4分
1 n
(2)设b =n+3na =n+36n −4n3n,
n n
n(n+1) 18
( 1−6n)
则S = + −4n3n ························································· 6分
n 2 1−6
设T =4n3n,
n
T =431+832 +1233+ +4n3n,
n
3T =432 +833+1234+ +4n3n+1 ····················································· 7分
n
作差得到2T =−431−432 −433− −43n +4n3n+1 ······························ 8分
n
−6
( 1−3n)
故T = +2n3n+1 =(2n−1)3n+1+3 ·········································· 10分
n 1−3
n(n+1) 18
( 1−6n)
S = + −T
n 2 1−6 n
n2 n 18 33
故S = + + 6n −(2n−1)3n+1− ················································ 12分
n 2 2 5 5
19.(12分)
(1)圆C 的方程可变形为(x−2)2 + y2 =4 ···························································· 2分
1
故C 的圆心坐标为 (2,0) ,半径为2 ······························································· 4分
1
(2)设M (x ,y ) ,因为点M是AB的中点,CM ⊥ AB,
M M 1
k k =−1 ························································································ 6分
CM AB
1
y y
故 M M =−1 ················································································ 8分
x −2 x −1
M M
第2页 共5页
{#{QQABbYAEggCAQBIAAQhCAwGYCAGQkACCCKoOABAEsAAAyRNABCA=}#}由此可得x2 −3x +y2 +2=0 ··································································· 10分
M M M
3 2 1 3 1
故轨迹方程为
x −
+ y2 = ,轨迹是以圆心为 ,0 ,半径为 的圆 ······· 12分
M 2 M 4 2 2
20.(12分)
(1)解:10x+100.005+100.01+10y+100.019+100.02+100.027=1,
故x+ y=0.019 ························································································· 1分
20010y−20010x=22,
故y−x=0.011 ························································································· 2分
解得x=0.004,y=0.015 ············································································ 3分
(2)①学院毕业生年薪在
30,80)
区间的人数比例为:
(0.02+0.027+0.015+0.01+0.005)
10=77%,
故同类型合作办学高校毕业生平均年薪最高为30万元 ········································ 5分
②对于单个毕业生,其年薪高于50万的概率P=(0.005+0.01+0.015)10=0.3,
3
故随机变量~ B 4, ,
10
故P(=0)=(1−0.3)4
=0.2401 ·································································· 6分
P(=1)=C1(1−0.3)3
0.3=0.4116 ························································ 7分
4
P(=2)=C2(1−0.3)2 0.32 =0.2646 ······················································ 8分
4
P(=3)=C3(1−0.3)0.33 =0.0756 ······················································· 9分
4
P(=4)=0.34 =0.0081 ········································································· 10分
的分布列为:
0 1 2 3 4
P 0.2401 0.4116 0.2646 0.0756 0.0081
第3页 共5页
{#{QQABbYAEggCAQBIAAQhCAwGYCAGQkACCCKoOABAEsAAAyRNABCA=}#}的数学期望E()=0.34=1.2
······························································· 12分
21.(12分)
(4x−a)ex −ex( 2x2 −ax+a ) −2x2 +(a+4)x−2a
(1) f(x)= = ······················· 2分
( ex)2 ex
−2x2 +5x−2
当a=1时, f(x)= , f(0)=−2 ············································ 4分
ex
又 f (0)=1,故曲线y = f (x) 在 ( 0, f (0)) 处的切线方程为y=−2x+1 ············ 5分
−2x2 +(a+4)x−2a (−2x+a)(x−2)
(2) f(x)= = =0,
ex ex
a
解得知x =2,x = ··················································································· 7分
1 2 2
a a
若a>4, f (x) 在 (−,2), ,+ 递减, 2, 递增 ······································· 8分
2 2
a a
f = >0
极大值 ··············································································· 9分
2 a
e2
若a=4,函数单调递减,无极大值 ····························································· 10分
a a
若a<4, f (x) 在 −, ,(2,+) 递减, ,2 递增 ····································· 11分
2 2
8−a
极大值 f (2)= >0 ············································································ 12分
e2
综上, f (x) 的极大值恒为正数.
22.(12分)
x2 ( ) ( )
(1)椭圆E: + y2 =1的左,右焦点分别为F − 3,0 ,F 3,0 ,
1 2
4
设A(m,n),AF ⊥ AF ,故AF AF = ( − 3−m,−n )( 3−m,−n ) =0 ··············· 1分
1 2 1 2
即m2 +n2 =3 ··························································································· 2分
m2 2 6 3
又 +n2 =1,解得m= ,n= ························································· 3分
4 3 3
2 6 3
A点坐标为 , ············································································ 4分
3 3
第4页 共5页
{#{QQABbYAEggCAQBIAAQhCAwGYCAGQkACCCKoOABAEsAAAyRNABCA=}#}(2)设P点坐标为 (p,0) ,则可得Q点坐标为 ( 2 6−2p, 3 ) ································· 5分
2
( )
6
OPOQ=(p,0) 2 6−2p, 3 =−2p2 +2 6p=−2p− +3 ················· 7分
2
6
当 p = 时,OPOQ取最大值,最大值为3 ················································ 8分
2
2 6 3 2 6 3
(3)A点坐标为 , ,B点坐标为− , ,
3 3 3 3
3
点O到线段AB的距离h = ····································································· 9分
1 3
3
若S =2S ,则点M到线段AB的距离应为h = ,
1 2 2 6
3 3
故M点的纵坐标为 或 ,代入椭圆方程,
6 2
33
解得M点的横坐标为 或1 ······························································· 11分
3
33 3 3
故M点的坐标为: , 或1, ·············································· 12分
3 6 2
第5页 共5页
{#{QQABbYAEggCAQBIAAQhCAwGYCAGQkACCCKoOABAEsAAAyRNABCA=}#}