已知四棱锥
中,底面是直角梯形,
,
,
,侧面
是以
为直角的等腰三角形,且侧面
与底面
垂直.
![](https://img.xkw.com/dksih/QBM/2017/4/28/1675418249404416/1679795616350208/STEM/0a55b9bceab348ea888a11f46172fcb3.png?resizew=222)
(I)求证:
;
(II)若点
为侧棱
上的一动点,问点
在何位置时,二面角
的余弦值为
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/faeb97acf19bd3b2c6c77c2814df4d2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e921f46d90e43f4517c55832b6280f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8af620f6d204d310d8e3f267fdd6c3f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d923a338dd2d2e29336b42574d38448.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c52e7222eb3978fd85e743d084a9e5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d923a338dd2d2e29336b42574d38448.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://img.xkw.com/dksih/QBM/2017/4/28/1675418249404416/1679795616350208/STEM/0a55b9bceab348ea888a11f46172fcb3.png?resizew=222)
(I)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fe0bb7d51e559e73aa16a954fe7fa33.png)
(II)若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d4db9b82b67efe45a02fca32bfcf5dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/977c07a8bc54f8d1ad72cd9048058afc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dee14db57f0c762aad845cf5b4a243c0.png)
更新时间:2017-05-04 16:55:50
|
相似题推荐
解答题-证明题
|
适中
(0.64)
【推荐1】在如图的多面体中,EF⊥平面AEB,AE⊥EB,AD∥EF,EF∥BC,BC=2AD=4,EF=3,AE=BE=2,G是BC的中点.
![](https://img.xkw.com/dksih/QBM/2016/1/22/1572462281269248/1572462287331328/STEM/a677a6ec39c6487db4f439213e599586.png)
(Ⅰ)求证:AB∥平面DEG;
(Ⅱ)求证:BD⊥EG.
![](https://img.xkw.com/dksih/QBM/2016/1/22/1572462281269248/1572462287331328/STEM/a677a6ec39c6487db4f439213e599586.png)
(Ⅰ)求证:AB∥平面DEG;
(Ⅱ)求证:BD⊥EG.
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐2】长方体
中,E是BC的中点,M、N分别是AE、
的中点,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4aeca3cbfb632d017d8720942eb7f1d0.png)
.
(1) 求证:
平面
;
(2)求异面直线AE与
所成角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e539f26ed5e0b20ff7220559324869a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4aeca3cbfb632d017d8720942eb7f1d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d7df9443fda28f9c1027add9f072466.png)
(1) 求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edcf19a7f0dd0cdf59516ae585025110.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ebb05874eb3353d754af24c9974273e.png)
(2)求异面直线AE与
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e539f26ed5e0b20ff7220559324869a4.png)
![](https://img.xkw.com/dksih/QBM/2011/3/29/1570083507953664/1570083513548800/STEM/5efb8feba64f4522b5927f617baa9c7a.png?resizew=205)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐1】如图,在三棱锥
中,点
为
的重心,点
在
上,且
,过点
任意作一个平面分别交线段
,
,
于点
,
,
,若
,
,
,求证:
为定值,并求出该定值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e3317d8b5ad853642b2f35e0d668415.png)
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解答题-证明题
|
适中
(0.65)
【推荐2】如图,在平行六面体
中,
,
,
,
(1)求
;
(2)求证:
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cead0e8eadfdcefa334953e88864f424.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6906f59d09ce31956d6f5ea2b23fc77.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7362be3007eef9e6cdcbdbdad769eab7.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b448365344987329313d7489c756d738.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a5928c98b341b16d4b5a5b931d2929d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d9a8181f7a7fe7f3fac872ce9534f15.png)
![](https://img.xkw.com/dksih/QBM/2012/2/20/1570755401695232/1570755406807040/STEM/7086ca2ef0864288a92edfb40ba20846.png?resizew=324)
您最近一年使用:0次
解答题-问答题
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适中
(0.65)
【推荐1】已知在正方体
中,边长为2,
分别是
的中点,求点
到
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea47d5f616b648736ae5fa8f1921c964.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐2】如图,在四棱锥
中,底面ABCD是边长为1的正方形,侧棱PA的长为2,且PA与AB、AD的夹角都等于60°,M是PC的中点,设
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/22/8c8e1d12-57a3-48cb-b028-78df98232236.png?resizew=153)
(1)求证
;
(2)求BM的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e7a93a1399ff7a2bde342652479241b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3b54aa2b7f9adf409f0ce8e00615432.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e28eb023fe260d9b50fcc441e1df95e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/22/8c8e1d12-57a3-48cb-b028-78df98232236.png?resizew=153)
(1)求证
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c4a08422947cfb7d16535225bdc2935.png)
(2)求BM的长.
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解答题-问答题
|
适中
(0.65)
【推荐1】如图,正方体
的顶点坐标为
,
,
,
,
,
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b32ab04dd852329d5918b177c199eee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e2755d7f7751444a6ee6de623bdd836.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8978311495c4dcc0a65bc0a6c8e4c7c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/652901d0cbdc66440cd2ffd9b1cb1aac.png)
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您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
解题方法
【推荐2】如图,在四棱锥
中,底面
是正方形,侧棱
底面
,
,点
是
的中点,
在直线
上.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/15/30af9cba-7456-44ab-bba1-c59334d2e408.png?resizew=143)
(1)若
,求
的值;
(2)求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.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/40d4d36ae30487030b827ce9413b9f13.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/15/30af9cba-7456-44ab-bba1-c59334d2e408.png?resizew=143)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc2484662ae40c406b054d14a7f9e118.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7aafecdff4e61f7e74e06db9b31c826c.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e5777a34d4761364c48e2b53ab79ff1.png)
您最近一年使用:0次