已知边长为
的正
的顶点
在平面
内,顶点
,
在平面
外的同一侧,点
,
分别为
,
在平面
内的投影,设
,直线
与平面
所成的角为
.若
是以角
为直角的直角三角形,则
的最小值为__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2df93bd15f25096c510b589aad0dfc1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3953cec61ac602ce5eb59b7912352179.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4c8a9c4957431681ddfc77895a88508.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e0570daec75ad24fa7eadea514aa2c8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ffb952f86442845da723fd291564484.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e163a27fe00deaf1cc00f1d3d943770.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6581916f5a65edfea257c804efee007e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8ee6e1d480ece7117e1f87ebf4bbeea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2bb786ffc73703c5b88a4343cd90ab00.png)
更新时间:2018-07-04 21:24:25
|
相似题推荐
填空题-单空题
|
适中
(0.65)
名校
解题方法
【推荐1】在正方体
中,点
是棱
的中点,点
是线段
上的一个动点.有以下三个命题:
①异面直线
与
所成的角是定值;
②三棱锥
的体积是定值;
③直线
与平面
所成的角是定值.
其中真命题的是___________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56f7ba05c54b3de1f4378f7c8eb58328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e539f26ed5e0b20ff7220559324869a4.png)
①异面直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24bb49fdc6b6bbb2449fdf8a0de769d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3fc725182c2fd1413319fea35b95c7dc.png)
②三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5210296963a878798a2d324e981457d7.png)
③直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f35f348ed8a1690d3ed02aa64459ca50.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b0a582c36d62d83c16425b2f54b4354.png)
其中真命题的是
![](https://img.xkw.com/dksih/QBM/2021/10/7/2823997406011392/2825526451765248/STEM/04e38db72fdd47dba4c86b93c2ab4a0f.png?resizew=201)
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【推荐2】
是两个平面,
是三条直线,有下列四个命题:
①若
,则
;
②若
则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79018590293277ff2d76452a50ad2dbc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e45bcd8f6ede8cc2513ad41402f40086.png)
③若
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dfb21c3b76b06a423aeef09fe7d74a2.png)
④若
则
与
所成的角和
与
所成的角相等.
其中正确的命题有_____
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4e288596fa3811dd2c17bded60e82e7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2f682870aa63eea67a9f3133b3dabac.png)
①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61e4fb3142b471e6fc7a5f90835303ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21d73ad9021fc4df50106faf32845d2d.png)
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a00956a74f7de72ffcf8db9abbc7406.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79018590293277ff2d76452a50ad2dbc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e45bcd8f6ede8cc2513ad41402f40086.png)
③若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c55f24dca900a89a369a14baee6484fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dfb21c3b76b06a423aeef09fe7d74a2.png)
④若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a7d6626b1c8d03bf6e430d5891fbec5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
其中正确的命题有
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【推荐1】设E,F分别是正方体ABCD﹣A1B1C1D1的棱DC上两点,且AB=2,EF=1,给出下列四个命题:
①三棱锥D1﹣B1EF的体积为定值;
②异面直线D1B1与EF所成的角为45°;
③D1B1⊥平面B1EF;
④直线D1B1与平面B1EF所成的角为60°.
其中正确的命题为_____ .
①三棱锥D1﹣B1EF的体积为定值;
②异面直线D1B1与EF所成的角为45°;
③D1B1⊥平面B1EF;
④直线D1B1与平面B1EF所成的角为60°.
其中正确的命题为
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解题方法
【推荐2】如图,在棱长为6的正方体
中,
为棱
上一点,且
为棱
的中点,点
是线段
上的动点,则下列说法正确的是______________
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/26/102d1c92-c861-4ad1-9920-6b98caec60f0.png?resizew=230)
①无论点
在线段
上如何移动,都有![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27aa0ded1ed76baa2ec1c6bea9f97edd.png)
②四面体
的体积为24
③直线
与
所成角的余弦值为![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d0c78f09a6621b15a9b3597b20dcc6e.png)
④直线
与平面
所成最大角的余弦值为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22adbc0da438220f9cace11b629d799b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/509f92ae9db2de73aadc114c04d6e183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f66fb71b75b63594ebeeeebd1963eed5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d8772aa893a9c1d40f714cb25701701.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/26/102d1c92-c861-4ad1-9920-6b98caec60f0.png?resizew=230)
①无论点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d8772aa893a9c1d40f714cb25701701.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27aa0ded1ed76baa2ec1c6bea9f97edd.png)
②四面体
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccc3bf74119692ac98eb24fcfa2a3f9f.png)
③直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d0c78f09a6621b15a9b3597b20dcc6e.png)
④直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04777f3f4661fa1c08a1cc0dfb807c7d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bf9628142422a4884bd59538da6d312.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dac452fbb5ef6dd653e7fbbef639484.png)
您最近一年使用:0次