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高一数学参考答案 第 1 页 共 4 页
2020~2021 学年第一学期期中考试
高一数学参考答案及评分标准
一、单项选择题:共 8 小题,每小题 5 分,共 40 分.
1.A 2.B 3.D 4.C 5.B 6.A 7.C 8.B
二、多项选择题: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,部分选对的得 3 分,有选错的得 0 分.
9.AC 10.AC 11.BD 12.ABD
三、填空题:共 4 小题,每小题 5 分,共 20 分.
13.3 14.8 15.30 16.36
四、解答题:共 6 小题,共 70 分.解答时写出必要的文字说明、证明过程或演算步骤.
17.(本小题满分 10 分)
解:若选择①因为 ( )( 1) 0A x x a x a ,故 ( , 1)A a a ; ························· 3 分
A B B ,则 A B , ········································································· 5 分
所以
1,
1 1,
a
a
≥
≤
······················································································ 8 分
解得 1 0a ≤ ≤
所以选择①,实数 a 的取值范围是[ 1, 0] . ··············································· 10 分
若选择②因为 ( )( 1) 0A x x a x a ,故 ( , 1)A a a ; ······························· 3 分
因为 A B ,
所以 1 1a ≤ 或 1a≥ , ·········································································· 6 分
解得 2a ≤ 或 1a≥ , ············································································· 8 分
所以选择②,实数 a 的取值范围是 ( , 2] [1, ) . ································· 10 分
若选择③因为 ( )( 1) 0A x x a x a ,故 ( , 1)A a a ; ······························· 3 分
因为 A B B ,则 B A ······································································ 5 分
所以
1,
1 1,
a
a
≤
≥
····················································································· 8 分
所以 a
所以选择③,实数 a 不存在. ································································· 10 分
高一数学参考答案 第 2 页 共 4 页
18.(本小题满分 12 分)
解:(1)由
3 0,
1 0
x
x
≥
≥
得 1 3x ≤ ≤ ,所以 1,3A ; ········································· 3 分
又
22
( ) 2 3 1 2 2g x x x x ≥ ,所以 2,B . ······························ 6 分
(2)由(1)知 1,3 2, 1,A B ; ······································ 9 分
因为 , 2U B , ·······························