1 . 在正四棱锥
中,
为正方形
的中心,
,且平面
与直线
交于
,
,则
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04582116cd765fcc5a52f44279ad6c94.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0002aa62216db32e48112b513aa92f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09afc70f448545336304333d5b5658b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db0d8a42886898075cc54743b7f41c4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd995178601c2ad7b40f973d268c7bb7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04582116cd765fcc5a52f44279ad6c94.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
您最近一年使用:0次
2 . 如图,正方体
棱长为
,点
分别在直线
上, 若直线
与棱
相交, 则
的最小值是.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00d061c7a9c98768ead226c27bdfd2f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f66fb71b75b63594ebeeeebd1963eed5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8fc8967f2d98d71069fb0d1d59d1068.png)
![](https://img.xkw.com/dksih/QBM/2016/11/25/1573181629947904/1573181636198400/STEM/9090256e-55cf-4d97-a320-1390455b6af7.png)
您最近一年使用:0次
3 . 对于以下命题:
①
是
共线的充要条件;
②对空间任意一点O和不共线的三点A、B、C,若
,则P、A、B、C四点共面.
③如果
,那么
与
的夹角为钝角
④若
为空间一个基底,则
构成空间的另一个基底;
⑤若
,则
.
其中不正确结论的序号是___________________ .
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/064afaec7cc0740973902f76f2f60fad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b172cf8d898883d82e973f28c3c3a3e.png)
②对空间任意一点O和不共线的三点A、B、C,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e739c2d4754a7421f8b20e3b5bc09074.png)
③如果
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eca3cad5218bc14bf4c1a382db5f00c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb80eb942aafb194fadc473776f35b1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/433b94c39737727e53468df419d8314a.png)
④若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ed18a92338c7578c18a5ba3a2ae1ed4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4168c5c168c00a5337ad92b63a867cdf.png)
⑤若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a618330d2faa57c308ccf92ca88079b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/242b0af4f33851007b2052508dd3790e.png)
其中不正确结论的序号是
您最近一年使用:0次
12-13高二上·山东济宁·期末
4 . 若空间三点
共线,则
=_________ ;
=_________
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/880d189c0d94a5ed5057481848cce2fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1010846eeec6c9da29640f5aa3f8738.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
您最近一年使用:0次
11-12高二上·四川雅安·阶段练习
5 . 给出下列命题:
①已知
,则
;
②
为空间四点,若
不构成空间的一个基底,那么
共面;
③已知
,则
与任何向量都不构成空间的一个基底;
④若
共线,则
所在直线或者平行或者重合.
正确的结论为_________________ .
①已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa5aa846a5b7c96fe2ce665eb1ea5f0e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9abe3129df258837fdb4a0aca22e805d.png)
②
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d63368fb5c4feebe59c81bd5c90d8eaf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4451f3742c3b50f818371fa36a8301d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d63368fb5c4feebe59c81bd5c90d8eaf.png)
③已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa5aa846a5b7c96fe2ce665eb1ea5f0e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8ccba3b87a8a48ac3dd5f72d00bdb1a.png)
④若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8ccba3b87a8a48ac3dd5f72d00bdb1a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8ccba3b87a8a48ac3dd5f72d00bdb1a.png)
正确的结论为
您最近一年使用:0次