1 . 在实数集R中,我们定义的大小关系“>”为全体实数排了一个“序”.类似的,我们在平面向量集
上也可以定义一个称“序”的关系,记为“
”.定义如下:对于任意两个向量
,“
”当且仅当“
”或“
”.按上述定义的关系“
”,给出如下四个命题:
①若
,则
;
②若
,则
;
③若
,则对于任意
;
④对于任意向量
,若
,则
.
其中真命题的序号为__________
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a965af9e5b642eac59f2cce02a66d66.png)
![](https://img.xkw.com/dksih/QBM/2014/12/26/1571936737443840/1571936743333888/STEM/b23a3e6395414191af332e0bc940a28c.png?resizew=23)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41aed82593c7243215fb61bd72396407.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7fa7079dfcebe900aa27605981e4a76c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2210f152080d9a68a97c805f5c1cde96.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f088dba1c49a90372d33f199373f6ea7.png)
![](https://img.xkw.com/dksih/QBM/2014/12/26/1571936737443840/1571936743333888/STEM/b23a3e6395414191af332e0bc940a28c.png?resizew=23)
①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/378d6b5612e51eacc7071a2e5cd9b09e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/364169e800302ecdbac0fc45931e9c22.png)
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b48bd5a837ffd88aba5eab249b43a206.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd7c5aa14174df024274c2ab8912f7b9.png)
③若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7fa7079dfcebe900aa27605981e4a76c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fd5cce0d8ba711ab80c4e0452ea9dc9.png)
④对于任意向量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5cd5ae1973dec0e19abf9a8cd08315c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7fa7079dfcebe900aa27605981e4a76c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaf62422562ca7208352128beb54f4e6.png)
其中真命题的序号为
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