如图,在等腰梯形
中,
,
,
,四边形
为矩形,平面
平面
,
.
![](https://img.xkw.com/dksih/QBM/2017/8/18/1754646366486528/1754934347112448/STEM/839d63a55d82455e8b94cb76be254a8c.png?resizew=174)
(1)求证:
平面
;
(2)求多面体
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49149989ccd8350bf530c7cb750f7014.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a75b1354b8b783a65ee5e3bc596a976.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b43186930d4b6e1417aaa2cc7c039e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bbc56d42b003cbcb1fbe5c50e55b26b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c0db1f4f666a9be9ede868065a50997.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3362a45b72536c714c5107b0ae94f1c7.png)
![](https://img.xkw.com/dksih/QBM/2017/8/18/1754646366486528/1754934347112448/STEM/839d63a55d82455e8b94cb76be254a8c.png?resizew=174)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2ffc6952e988d04f22f0fb2f7f0ab7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bbc56d42b003cbcb1fbe5c50e55b26b.png)
(2)求多面体
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9165d9bfbb0f0d19eb482c2a4c1b29b7.png)
更新时间:2017-08-18 20:45:58
|
相似题推荐
解答题-问答题
|
适中
(0.65)
【推荐1】被嘉定著名学者钱大昕赞誉为“国朝算学第一”的清朝数学家梅文鼎曾创造出一类“方灯体”,“灯者立方去其八角也”,如图所示,在棱长为
的正方体
中,点
为棱上的四等分点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/6/8033fbda-c25e-4863-bb8c-a41ceef63c4d.png?resizew=209)
(1)求该方灯体的体积;
(2)求直线
和
的所成角;
(3)求直线
和平面
的所成角.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8860d9787671b53b1ab68b3d526f5ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/560b6c42bdce1d950245a5e1ed37537f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/6/8033fbda-c25e-4863-bb8c-a41ceef63c4d.png?resizew=209)
(1)求该方灯体的体积;
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4a949c00526fddf435423272cf10f25.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1be0c48c7f4a070e0d7f4de345679367.png)
(3)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a0b46fa6746c09ef4120e7256326151.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bd8081131102151e01fcaf6ee67acd4.png)
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【推荐2】如图,
为圆锥的顶点,
为圆锥底面的圆心,
为底面直径,
为底面圆周上一点,
,四边形
为矩形,点
在
上,且
平面
.
![](https://img.xkw.com/dksih/QBM/2022/5/6/2973651645530112/2974963590799360/STEM/68b66aa8-c580-412a-8ce6-923d1ec1ca0c.png?resizew=289)
(1)请判断点
的位置并说明理由;
(2)平面
将多面体
分成两部分,求体积较大部分几何体的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cfe71b1bd5d58b604e0f1ff775fb92a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d2806aad4bdfa727f3d4150434ab055.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a2b5cfae407016cad45bbdefea05833.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca48c18021e7be4bbb3e95576e1c1b5f.png)
![](https://img.xkw.com/dksih/QBM/2022/5/6/2973651645530112/2974963590799360/STEM/68b66aa8-c580-412a-8ce6-923d1ec1ca0c.png?resizew=289)
(1)请判断点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
(2)平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c761098c711ffc8ad047a6867d2a268.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18145e24844c08cb2cc05f69cfbb1c5a.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐1】如图,在三棱柱
中,平面
平面
,
.
,
为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/23/5f010224-ecaa-4f86-af86-54f4b4c79dd7.png?resizew=187)
(1)求证:
平面
;
(2)求证:直线
与
不垂直;
(3)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61cdaadeae37736a1e6dd93fa1fe712f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44ae6e1fdf5a4675c439b0d4e0362725.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b33ad89b19e4e089c0d03cd6efae9ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/23/5f010224-ecaa-4f86-af86-54f4b4c79dd7.png?resizew=187)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f6d39135a2f8472d66ea00eda3b13ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
(2)求证:直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f1f229274a6e17977cc047814212589.png)
(3)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/174be5a45bdb0e8695350ee47e1293e4.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
解题方法
【推荐2】如图,在正三棱柱
(底面为正三角形的直棱柱)中,
,
为
的中点,
为侧棱
上的点.
![](https://img.xkw.com/dksih/QBM/2022/11/28/3119366565789696/3120963764862976/STEM/1c82dbbb2b084c20bd3c7e930c79b75f.png?resizew=169)
(1)当
为
的中点时,求证:
平面
;
(2)是否存在点
,使得三棱柱被平面
分成的上下两部分体积关系为
,若存在,求
的长,若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bae07e0018faaeb9365b82e1be8c193d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://img.xkw.com/dksih/QBM/2022/11/28/3119366565789696/3120963764862976/STEM/1c82dbbb2b084c20bd3c7e930c79b75f.png?resizew=169)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a5edfe97aeab0cf16b40fa9d2e15f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea84e9242d2667cd6a0f7436425ad418.png)
(2)是否存在点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea84e9242d2667cd6a0f7436425ad418.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/598814aa24eed727fc46eb77fd53e5ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
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