如图,以正四棱锥
的底面中心
为坐标原点建立直角坐标系
,其中
,
,
为
的中点,正四棱锥的底面边长为
,高为
.
;
(2)当
是二面角
的平面角时,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ebfcf34539673d516eb9b259951a81ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5e336d6ca2cae3d6e6c3810d7e521a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6186f4e09027dc44549c649eaac86a08.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03dae79cccdba77e49e7bd9c933430d8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a392d05d3cfcbb438569b1ea9980dc2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/878e89b6eca35e34c863e832a2c661db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3eabd5f3a86afe49dcd70571e2b96cfd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e1ff14e3983dcfbc0022fc817cc6d66.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb3de20ba8bda63c650ef571be155702.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080357c95392e1c1831d999893ec6e77.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb3de20ba8bda63c650ef571be155702.png)
更新时间:2021-12-10 12:23:43
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相似题推荐
解答题-证明题
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解题方法
【推荐1】棱长为2的正方体中,E,F分别是
,
的中点,G在棱CD上,且
,H是
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/30/c5bf07ba-ea16-4fb2-b13a-0c1261be1af9.png?resizew=166)
(1)证明:
;
(2)求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22adbc0da438220f9cace11b629d799b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d97dc3b752832906de41447bb58a341.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6de2ee944c8c3476e3014050f0e36199.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2fec5bd77cfc1313bc200480cc66c766.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/30/c5bf07ba-ea16-4fb2-b13a-0c1261be1af9.png?resizew=166)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d435974639ea2850bb5c21efe64b123b.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1cb5df5027f54013c6e4b9610b5c20e.png)
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【推荐2】已知空间三点
.
(1)求以AB,AC为邻边的平行四边形的面积;
(2)若向量
分别与
垂直,且
,求
的坐标.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab57dc75393d9df0860efd60be49398c.png)
(1)求以AB,AC为邻边的平行四边形的面积;
(2)若向量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c5562bd4d1b54424330cb6329cd79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0be656083580a03c6481fb75881b84f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e876fd1923d49d54908825bedaa9a8a6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c5562bd4d1b54424330cb6329cd79d.png)
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【推荐1】在四棱锥
中,底面是边长为2的正方形,
平面
,
,
是棱
上一点.
为
的中点,求直线
与平面
所成角的正弦值;
(2)若平面
与平面
的夹角的余弦值为
,求点
的位置.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e0f73b3c63084d9c032802e01f9a168.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46e2da608b66c9aee03e2503388ba4fd.png)
(2)若平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46e2da608b66c9aee03e2503388ba4fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3fa3ba9c03ed22792d22d01518fcf40.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
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【推荐2】如图,直三棱柱
中,底面是边长为2的等边三角形,D为棱AC中点.
![](https://img.xkw.com/dksih/QBM/2022/2/18/2919195927617536/2947527911251968/STEM/96196a70-cb98-4b49-9cb9-a0f894d50d9f.png?resizew=150)
(1)证明:AB1//平面
;
(2)若面B1BC1与面BC1D的夹角余弦值为
,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://img.xkw.com/dksih/QBM/2022/2/18/2919195927617536/2947527911251968/STEM/96196a70-cb98-4b49-9cb9-a0f894d50d9f.png?resizew=150)
(1)证明:AB1//平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a935b7d21a103a264b6e96ecf82dbe4a.png)
(2)若面B1BC1与面BC1D的夹角余弦值为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b2a698891d42c70b597f0da4f215f09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
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【推荐3】在
中,
,
,
分别
上的点且
,
,将
沿
折起到
的位置,使
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/23/18ae9419-da1e-4a0f-9da9-10334277603b.png?resizew=224)
(1)求证:
;
(2)是否在射线
上存在点
,使平面
与平面
所成角的余弦值为
?若存在,求出
的长度;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e3262fc038bbec5e7c8cc47df08bef7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1636c0562f0438a892d9df679e9e08d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91e1e4115d78e625e9e0f47cdade3286.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf9a415bdb7b4e1e35c18a9e53205392.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bad8f19018ce02050585d6bd6e0bc0bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/377b5f7197e5bd1afeea4d931307956a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.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/cdb2fef4031c10abc18c8747af6b9a8a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/23/18ae9419-da1e-4a0f-9da9-10334277603b.png?resizew=224)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01676a558e64ef15c9afacbc7acda293.png)
(2)是否在射线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e75d14708e6aa1404477db9d7e3166f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43819ab7b268a6293a9251935b594690.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6994042288fbd7cdf7d0f2d83e3afa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ed24aeda4260685f4e1bd6b78a8ff25.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15a424b50eaeafa6f302ffd95476cb86.png)
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