2020-2021 学年度 第二学期 期末学业水平诊断
高一数学参考答案
一、选择题
C A C D B C D A
二、选择题
9.AC 10.BCD 11.ABD 12.ACD
三、填空题
2222 28
13. 366
0.94 14. 15.SSSS????ABC ACD ADB BCD++= 16. π
6 3
四、解答题
17.证明:( 1) 连接 BD,因为 EF, 分别 为棱 ABAD, 的中点 ,
A
11
所以 EF BDEF BD// , = . ································· 2分 E F
22
B D
11 G
同理 HG BDHG BD// , = . ································ 4分 H
22 C
所以 EFGH// 且 EFGH= . ·································· 5分
所以四边形 EFGH 是平行四边形 . ···························· 6分
( 2)当 ACBD⊥ 且 ACBD= 时 ,四边形 EFGH 为 正方 形 . ····················· 10分
18.解:( 1)设 事件 ABCD,,, 分别表示“ 被 评为 等级 ABCD,,, ”.
由题意, 事件 ABCD,,, 两两互斥 ,
3131
所以 PD()1=???= . ························································· 2分
483232
又 CD? = “延迟 送达且被罚款 ”,
1
所以 PCDPCPD( )()()? =+= . ······················································ 4分
8
1
因此 “延迟 送达且被罚款 ”的概率 为 . ················································· 5分
8
高 一 数学参考答案 第 1页 (共 5页 )
( 2) 设 事件 ABCDiiii,,, 表示 “ 第 i单被评为 等级 ABCD,,, ”, i=1,2.
则 “ 两单共获得 的 奖励 为 0元 ”即事件 ()()()AB AC AC22 12 21?? , ············· 7分
且事件 ABACAC221221,, 互斥,
111
又 PAB()22 =×= . ···································································· 8分
8864
339
又 PACPAC()()12 21= =×= . ·················································· 9分
432128
所以 PPAB AC AC= [( )( )( )]22 12 21??
=++PABPACPAC()()()22 12 21 ·············································· 10分
1133 5
=×+××=2 .························································· 12分
88432 32
19.解 :( 1)由题意 ,
4357611798694×+×+×+×+×+×
y = ··········································· 2分
40
=6.5. ·························································································· 3分
2 2221
sy =×?+×?+×?[3(46.5)7(56.5)11(66.5)
40
222
+×?+×?+×?9(76.5)6(86.5)4(96.5)] ······························· 5分
=1.95. ························································································ 6分
1
( 2)由( 1)可得, z xy= +(50 40) ······················································ 8分
90
1
= ×+×=(507.4406.5)7. ····································· 9分
90
22 250 40
sz = +?+×+?[2.6(7.47)] [1.95(6.57)] ································· 11分
90 90
113
= . ·················································································· 12分
45
高 一 数学参考答案 第 2页 (共 5页 )
20. 解( 1)证明:因为 ABAA⊥ 1, ABAC⊥ , ACAAA? 1 =
所以 AB ⊥平面 ACCA11, ································································· 2分
AC1 ?平面 ACCA11,所以 ABAC⊥ 1 . ··············································· 3分
又因为直三棱柱 ABCABC? 111中, AAAC1 = ,
所以四边形 ACCA11为正方形,所以 AC AC11⊥ . ··································· 4分
因为 ACABA1? = ,所以 AC1 ⊥平面 ABC1, ······································· 5分
BC1 ?平面 ABC1,所以 ACBC11⊥ . ···················································A1 6分
( 2) 过 A1作 ADBC1 11⊥ , 垂足为 D, 连 CD, 则 AD1 ⊥平面 BCCB11, B 1 C1
D
∠ACD1 为 AC1 与 平面 BCCB11所成的角 . ··················· 8分
因为 AAAC1 = =1,则 AC1 = 2 , A
B C
ADAD
所以 11 2 1
sin∠===ACD1 ,所以 AD1 = . ·························· 9分
AC1 2a 4 2
AD 1
在 1 ?
RtACD? 11 中, sin∠==ACD11 ,所以 ∠=ACD11 30 .
AC11 2
3
在 ?
RtABC? 111中, ABAC11 11= tan30 = . ······································ 10分
3
11 33
所以 VVAABC BAAC??11= =××××=11 . ································· 12分
32 3 18
21.解: ( 1)由已知 (0.0040.0060.020.030.024 101+++++×=m) , ············· 2分
解得 m=0.016. ············································································· 3分
( 2) 测试成绩的 平均数
x=×+×+×+×+×+×450.04550.06650.2750.3850.24950.16 ········· 4分
= .
76.2 ····················································································· 5分
测试成绩落在 区间 [40,70)的 频率为 (0.0040.0060.02100.3++×=) ,
落在 在区间 [40,80)的 频率为 (0.0040.0060.020.03100.6+++×=) ,
所以设 第 57百分位 数为 a,有 0.3 700.030.57+?×=(a ) , ·················· 6分
解得 a=79. ·················································································· 7分
高 一 数学参考答案 第 3页 (共 5页 )
0.243
( 3)由题知,测试分数位于区间 [80,90)、 [90,100)的人数 之 比 为 = ,
0.162
所以采用分层 随机 抽样 确定 的 5人, 在 区间 [80,90)中 3人 , 用 AAA123,, 表示, 在
区间 [90,100)中 2人 , 用 BB12, 表示 . ···················································· 8分
从这 5人中抽取 2人的所有可能情况有: (,)AA12 , (,)AA13 , (,)AB11 , (,)AB12 ,
(,)AA23 , (,)AB21 , (,)AB22 , (,)AB31 , (,)AB32 , (,)BB12 , 共 10种 . ······ 10分
其中 “ 落在区间 [80,90)和 [90,100)”有 6种 .··········································· 11分
3
所以 PA()= . ··················································································· 12分
5
1
22. 解:( 1)证明:取 AE中点 N , 连 MN , 则 MNDE// , MN DE= . ······ 1分
2 A
1
又因为 , M
BCDE// BC DE= ,
2 N
D
所以 E
BCMN// ,BCMN= . ··································· 2分
B
所以四边形 为平行四边形,所以 . C
BCMN BNCM// ···· 3分
又因为 BN ?平面 ABE,CM ?平面 ABE,
所以 CM //平面 ABE. ··········································· 5分
( 2) 延长 EBDC, 交于点 F , 则 AF 为平面 ABE与平面 ACD的交线 . ············· 6分
A
1 G
因为 BCDE// , BC DE= ,所以 BFBE= =2. M
2 N
D
三角形 ADE中,因为 ADDEAE= = =2,N 为 AE的中点 , E
所以 , B
DNAE⊥ C
又 因为 DEBE⊥ , AEBE⊥ , DEAEE? =
所以 BE ⊥平面 ADE, DN ?平面 ADE, F
所以 DNBE⊥ .
又因为 BEAEE? = , 所以 DN ⊥平面 ABE.
AF ?平面 ABE, 所以 DNAF⊥ . ························································ 8分
在三角形 AEF 中,过 N 作 NGAF⊥ ,垂足为 G,连 接 DG, 因为 DNNGN? = .
所以 AF ⊥平面 DNG, DG?平面 DNG,所以 AFDG⊥ .
所以 ∠DGN为二面角 DAFE?? 的平面角 . ············································ 9分
高 一 数学参考答案 第 4页 (共 5页 )
在 RTAEF? 中, AE EF= =2, 4,AF =+=41625,
AFAN
由 25
??AEF AGH? ,所以 = ,NG = . ··································· 10分
AEGN 5
在 25 22 95
RTDNG? 中, DN NG= =3, ,DG DN NG=+= ,
5 5
所以 NG 219
cos∠==DGN . ··························································· 11分
DG 19
即 面 ABE与 面 ACD所成 二面角 (锐角) 的余弦值为 219 . ······················ 12分
19
高 一 数学参考答案 第 5页 (共 5页 )