若
是空集,对于一特殊集合
来说,下列命题:
①
,②
,③
,④
中正确的个数为( ).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a837165ca03f9e4ea8964979c95e3bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8717b66f2d35b0bfc6414ad376d6fd53.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2ad921359a9626a10facd18074e6c02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddfac08c91395c5518819199f7629756.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc986be3f2d54e7b2bf5b5cb7dc27243.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d717091f41a082d6e1980c8d19648c7f.png)
A.1 | B.2 | C.3 | D.4 |
2018高三·全国·竞赛 查看更多[1]
更新时间:2019-01-20 13:37:20
|
【知识点】 集合的阶,集合之间的关系