1 . 设X,Y为任意集合,映射
.定义:对任意
,若
,则
,此时的
为单射.
(1)试在
上给出一个非单射的映射;
(2)证明:
是单射的充分必要条件是:给定任意其他集合
与映射
,若对任意
,有
,则
;
(3)证明:
是单射的充分必要条件是:存在映射
,使对任意
,有
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/86d7786f55f767e0a301b5032cdacc79.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4645f4c284aef83b9d7edc909ce75168.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33bd24e647a626899a243a3f3984f90a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f27822887caad20f3a075ca2fb74155c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca4ff0af96ea467337cb30c4c765b5f7.png)
(1)试在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff048206370cd239052751e22f51089e.png)
(2)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca4ff0af96ea467337cb30c4c765b5f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d8b9ad2fcfff3dd546c5fdbedfe6238.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/47d2e22788e03d6846442ce299b67bd7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/02ab73f0717678abfa9f8addc42be0c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce86cc928b228eba243c4bbfae8247ef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/683ee65c22bb8f6350feef3a3371a95f.png)
(3)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca4ff0af96ea467337cb30c4c765b5f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2216c6b89948de65d2e8488c2071a61.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fd9b15b5cdf1c131ebf7cf2776cf7a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e0ab2f691659dfb9857e81cabc3142e.png)
您最近一年使用:0次
2 . 函数
的解析式为
,值域为
,则符合要求的函数
的个数为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/942c2141d01bde6b48210c56a17fc75e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c565889556c2f415ba5c17e1c1ced41c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e565001c699e5e221ed616dd7be2bb83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
A.16个 | B.945个 | C.2025个 | D.1个 |
您最近一年使用:0次