20-21高一上·全国·课后作业
名校
1 . 给出下列命题,
①存在
、
,使得
;
②任何实数都有算术平方根;
③某些四边形不存在外接圆;
④
、
,都有
.
其中正确命题的序号为_______ .
①存在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d285a4c557fc9748105b62ccd94b7859.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddcf4daecd677a52d5f09849c18b63e4.png)
②任何实数都有算术平方根;
③某些四边形不存在外接圆;
④
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c780149aef1bd77162e85f7f8906a6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54dad48527a47eab4a5916ab0421cc71.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b437c89937a7cd619fa4498ae32e46b9.png)
其中正确命题的序号为
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2 . 判断正误(正确的打“正确”,错误的打“错误”)
(1)“有些”“某个”“有的”等短语不是存在量词.( )
(2)全称量词的含义是“任意性”,存在量词的含义是“存在性”.( )
(3)全称命题一定含有全称量词,存在量词命题一定含有存在量词.( )
(4)
与
的真假性相反.( )
(1)“有些”“某个”“有的”等短语不是存在量词.
(2)全称量词的含义是“任意性”,存在量词的含义是“存在性”.
(3)全称命题一定含有全称量词,存在量词命题一定含有存在量词.
(4)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2309b2d0889901147d77296fc7415807.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5a76ff223c49dc30218ac77c2991383.png)
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3 . 下列说法中不正确的是________ .(填序号)
①若
,则“
”是“
”的必要不充分条件;
②“
为真命题”是“
为真命题”的必要不充分条件;
③若命题![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58952ef6586cdd46086cd2acef0d41d6.png)
,则
是真命题;
④命题“
”的否定是“
”.
①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/848c33e3506416358d9f0d3ee66f67a9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03788c7bd5b9c006b33452100cc1a054.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1edc21a2299cf3e51e60186e5fab8b2.png)
②“
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/630acef0ef97721e9f030fb97705a49c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5638809efbb980cee614de77d718114.png)
③若命题
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58952ef6586cdd46086cd2acef0d41d6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/feed65016bec4e09cd88dc6de79aeb93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e434d52b7741e42c21c2785eb07ffcaf.png)
④命题“
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4884ab84c61111dc8057f819f10ca6c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30899fa8555b7b09960d9ecf87adddd2.png)
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4 . 以下关于命题的说法正确的有________ (填写所有正确命题的序号).
①“若
,则函数![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f45afdf4d717bb03adac6b899c367acb.png)
在其定义域内是减函数”是真命题;
②命题“若a=0,则ab=0”的否命题是“若a≠0,则ab≠0”;
③命题“若x,y都是偶数,则x+y也是偶数”的逆命题为真命题;
④命题“若
,则
”与命题“若
,则
”等价.
①“若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba2c58e340ebcea00ef2a6d05a836301.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f45afdf4d717bb03adac6b899c367acb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37b93abe2a497b7ef3cb8c1b9de8492e.png)
②命题“若a=0,则ab=0”的否命题是“若a≠0,则ab≠0”;
③命题“若x,y都是偶数,则x+y也是偶数”的逆命题为真命题;
④命题“若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/582ad43edf388c096e7704d92340bf75.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5286186cb58bf265a2a96e5195d88d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dab92728b35ed5798e07a2b0095bfcc1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a27dd329517f0dd8f1d0dfade6138ed4.png)
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