如图,在棱长为1的正方体
中,点P在线段
上运动,给出以下命题:
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/31/31a7bb5d-27af-44ec-bcad-1c9b0c9d7837.png?resizew=165)
①异面直线
与
所成的角不为定值;
②平面
平面
;
③二面角
的大小为定值;
④三棱锥
的体积为定值
其中真命题的序号为__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83c09eec4e14a861af83d7828797d176.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/31/31a7bb5d-27af-44ec-bcad-1c9b0c9d7837.png?resizew=165)
①异面直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c407eeb34204a1df967b8fbe481cb04d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7f6f93171329d508d491143b9d71f7b.png)
②平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9be92a3d03fd57eb64d2a01a60d1d9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4294ffdba16ae69fd03b13959d682aba.png)
③二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c55e158a95b9fc0fb606742e79cbb65.png)
④三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a80afb14665ad9cb3587c5364980e30.png)
其中真命题的序号为
更新时间:2021-05-17 09:10:30
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相似题推荐
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【推荐1】已知两平行平面
、
间的距离为
,点
,点
,且
,若异面直线
与
所成角为
,则四面体
的体积为____________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d84abdc67526dce4abec10b5a114c02d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b12712eb5c3454f89665e002a1784d5a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa8465a3f2e1a2b52a19075d84cda771.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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【推荐2】已知四面体ABCD的所有棱长都相等,其外接球的体积等于
,则下列结论正确的是___________ .(填序号)
①四面体ABCD的棱长均为2;
②四面体ABCD的体积等于
,
③异面直线AC与BD所成角为
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eefdcd39676298f214654051fc51ba92.png)
①四面体ABCD的棱长均为2;
②四面体ABCD的体积等于
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24c14ff9b66f21c05e52dc3c8908c2df.png)
③异面直线AC与BD所成角为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
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【推荐1】直线
、直线
是成
角的两条异面直线,点
为空间中一点,则过点
与直线
、直线
都成
角的直线有________ 条.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/260200d547998bcac50a4a491382e7f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/260200d547998bcac50a4a491382e7f4.png)
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【推荐2】如图,两条异面直线a,b所成角为
,在直线上a,b分别取点
,E和点A,F,使
且
.已知
,
,
.则线段![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f51d7fc14599a657b4831a4943360451.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b8df14d11c6f036b3b248544b731ae4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd72669c08e98a92cdfb9bc167ac56bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/078094de8f667321aa782b0f62242afb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae341f580ff8fbf21f616fe900b0e4b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e7c422a19b68b8b4cd484d22897e3a3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f51d7fc14599a657b4831a4943360451.png)
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【推荐3】如图,长为4,宽为2的矩形纸片
中,
为边
的中点,将
沿直线
翻转至
(
平面
),若
为线段
的中点,则在
翻转过程中,下列正确的命题序号是___________ .
![](https://img.xkw.com/dksih/QBM/2021/6/1/2733490475786240/2744083904757760/STEM/eccaa97d288b4699b3b370b300e6458a.png?resizew=203)
①
平面
;
②异面直线
与
所成角是定值;
③三棱锥
体积的最大值是
;
④一定存在某个位置,使
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3818a2c9919d358b4c3713396093822b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3aa2a83fed9bf4cb09d84a980452e346.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8588e18e27bfebf7c81c7e3c7efb1149.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://img.xkw.com/dksih/QBM/2021/6/1/2733490475786240/2744083904757760/STEM/eccaa97d288b4699b3b370b300e6458a.png?resizew=203)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8c70966a318ef8ecf874257f5c5e5db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/657dffbd3623b705f871878fbd9df57e.png)
②异面直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e69d2b798744645af88a4fa411344a83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ce1b066f8869d0ff4513f7a99745125.png)
③三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9666b03b544efac31b8f8ed7ddb7a427.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24c14ff9b66f21c05e52dc3c8908c2df.png)
④一定存在某个位置,使
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2181c78134c310f746eab44b9124e63b.png)
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【推荐1】设
,
是两条不同的直线,
,
是两个不同的平面.下列正确命题的序号是______ .
①若
,
,
,则
②若
,
,
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84b6e422b2e6f6dada4d8c369559a077.png)
③若
,
,
,则
④若
,
,
,则
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/539a38ada26356d73024fb8533449c49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/209323a7a4d015f7e570ec578c1731f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84b6e422b2e6f6dada4d8c369559a077.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5986f2991d45fbf3578f08f27d9fd7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35f747152f006301e03b643afb80195c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fe920cd78db25f5b4df37d066e57800.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f4ded3c4bc7a2212f2a0eb5f9753de5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84b6e422b2e6f6dada4d8c369559a077.png)
③若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5986f2991d45fbf3578f08f27d9fd7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fe920cd78db25f5b4df37d066e57800.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f4ded3c4bc7a2212f2a0eb5f9753de5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a93a52c2b943e4c70ace99ed802d2b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5986f2991d45fbf3578f08f27d9fd7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92c166c4d75211e5294eb440bf2a6350.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39344e476725f3fbae35f2e73377a38b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a53cd751c44ad4d9ebd8e3243e751321.png)
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【推荐2】在正四面体PABC中,D、E、F分别是AB、BC、CA的中点,下面四个结论中成立的____ .
①BC∥面PDF;②DF⊥面PAE;③面PDF⊥面ABC;④面PAE⊥面ABC.
①BC∥面PDF;②DF⊥面PAE;③面PDF⊥面ABC;④面PAE⊥面ABC.
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【推荐1】在正方体
中,下列命题中正确的是___________ .
①点
在线段
上运动时,三棱锥
的体积不变;
②点
在线段
上运动时,直线
与平面
所成角的大小不变;
③点
在线段
上运动时,二面角
的大小不变;
④点
在线段
上运动时,
恒成立.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
①点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d8772aa893a9c1d40f714cb25701701.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85669c44dfd3b3bc4ed8e441647c8b95.png)
②点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d8772aa893a9c1d40f714cb25701701.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da7977ab975efa6411cc17de39be70d9.png)
③点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d8772aa893a9c1d40f714cb25701701.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67094912ebf6dd7b27b835af55df4826.png)
④点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d8772aa893a9c1d40f714cb25701701.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f41b5345620564aaaa11d95eb8234ea.png)
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【推荐2】如图,
的二面角的棱上有两点
,直线
分别在这个二面角的两个半平面内,且都垂直于
,已知
,
,
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1ec5d678ec42846e1d28301e3bfd4be.png)
_______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ccfd81d120348601cd611241d1a5dc4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01c74a907dda6bb7d9d56d009d9df253.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73b3c032441543354c154ee67d744abb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71807a35b3170fce28ee6edf4c00d083.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7eb3d1070981fed5ca65a34bb2282e6f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1ec5d678ec42846e1d28301e3bfd4be.png)
![](https://img.xkw.com/dksih/QBM/2018/2/8/1878140872351744/1878725193654272/STEM/1a6e9979a1e94a2da5a03ef64ef832eb.png?resizew=192)
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