某中学的教师中,会英语及俄语的人总计 100人.据统计会英语有70人,会俄语的45人.求该校老师中会英语但不会俄语的人数.
2018高一·北京·竞赛 查看更多[1]
更新时间:2018-12-07 15:32:52
|
【知识点】 集合的阶,集合之间的关系
相似题推荐
解答题-问答题
|
适中
(0.65)
【推荐1】有理数集
的子集
有如下性质:
(1)如果
,
,则
,
;
(2)对于每个有理数
,
,
,
有且仅有一条成立.
试证明:
是由全体正有理数组成.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
(1)如果
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09256752badab8d69ae679796896ed97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77be3380e8b9628200a788b2695dbd32.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20d6fc9b90f370fbb27552876b650f8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3aa1230636571c84cd26a5ed282d243b.png)
(2)对于每个有理数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11bc05f41215f9894e11d1df0465751a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79d68051f49dc692f10c62ac27dc2a51.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e020c850c34c769732dc892f2daf3f54.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0116e1383a146ef6406d514764e87666.png)
试证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐2】设
是由整数组成的集合,满足:(1)对一切
、
,
,均有
;(2)存在
、
,使
.请问,
中是否必有元素0?
是否必定为无穷集合?说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e95d24952c1772d8db28522e5daff31e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22404ecc9b3ef48f2674c905008521bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a54f16c896d289d7cbe1dc6f9fa81898.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e95d24952c1772d8db28522e5daff31e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c27dd7d52809f198bec7854492661aa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e063f9c4e38ecae6d149c4b1c95dfc31.png)
您最近一年使用:0次