21-22高二·全国·课后作业
解题方法
1 . 如图,直角梯形
中,
,
,
,
,
为
的中点.把
折起,使
至
,若点
是线段
上的动点,则有下列结论:
![](https://img.xkw.com/dksih/QBM/2021/8/21/2790820932272128/2796441846169600/STEM/1e5e6bbc-7761-4dac-9dc1-5688e11c7bec.png?resizew=301)
①存在点
,使
平面
;
②对任意点
,使
与
成异面直线;
③存在点
,使
平面
;
④存在点
,使
平面
.
其中不正确的序号是__ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34e0a957a55460c72673c0f2ee90dbb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e0cdfb6d592897c6485ce1741677846.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b929269c53a44907dba8ee298a0a522.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc3814287dbb60d478bffc5366f9928b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a037b1a3ec2e37bbcb05d0a467efb511.png)
![](https://img.xkw.com/dksih/QBM/2021/8/21/2790820932272128/2796441846169600/STEM/1e5e6bbc-7761-4dac-9dc1-5688e11c7bec.png?resizew=301)
①存在点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c99cda5a272bbe32b28575fa51b9f6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b12cffc313a181f666e3fc8e66b6f59.png)
②对任意点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fd17a66a2af938c89e46f22e4d893b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/968b886a9f161fdcab1e08cba8ece5d0.png)
③存在点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21f9157fce2a8339d281178c7c0bccbe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b12cffc313a181f666e3fc8e66b6f59.png)
④存在点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69ce1507bc29b81f4a6594463c81ee0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3c87014fbb5c656a4f1892dbd88f242.png)
其中不正确的序号是
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