名校
解题方法
1 . 在正方体
中,点
为线段
上的动点.有下列结论:
①当
为
的中点时,
面积最小;
②无论
在线段
的什么位置,均满足
;
③存在一点
,使
;
④三棱锥
的体积为定值.
其中,所有正确结论的序号为____________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
①当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/153c1c37bcbec072dfcfb865bf4a4d20.png)
②无论
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4c0e33b9d4ed545cd32c69e5f668b9f.png)
③存在一点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58e2d8f2ecd57a48f0645a0c8d9e5779.png)
④三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/165a5001b1f0d8d89ed8e04607ac58ba.png)
其中,所有正确结论的序号为
您最近一年使用:0次
名校
2 . 如图,正方体
的棱长为1,
分别是线段
和
上的动点,则下列判断正确的是____________
请把所有正确命题的序号都填上![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04582116cd765fcc5a52f44279ad6c94.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/30/a1450777-0449-40ee-a96e-1d3324b54945.png?resizew=168)
①线段
的长度有最小值,且最小值为
;
②使
成立的点
的位置情况只有四种;
③不论
如何运动,线段
和
都不可能垂直;
④若
四点能构成三棱锥,则其体积只与点
的位置有关,与
无关;
⑤存在一个位置,使得
所在直线与四个侧面都平行.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7490886e2807c7b8a4fa57d99c4dc3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f1f229274a6e17977cc047814212589.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a301324443eb93b467134a86890dd9ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04582116cd765fcc5a52f44279ad6c94.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/30/a1450777-0449-40ee-a96e-1d3324b54945.png?resizew=168)
①线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
②使
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/056c2272e0d10d6dd9706e6324d8e62d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7490886e2807c7b8a4fa57d99c4dc3a.png)
③不论
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7490886e2807c7b8a4fa57d99c4dc3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87cdc08e1c4a04a18d5ecea03393e36d.png)
④若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/692fea42ab48808e343ed584e57ad12c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
⑤存在一个位置,使得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
您最近一年使用:0次