如图,在圆台
中,平面
过上下底面的圆心
,
,点M在
上,N为
的中点,
.
![](https://img.xkw.com/dksih/QBM/2020/2/9/2395180869443584/2395846742056960/STEM/c0002da49e9d4a6596eae2bff70bca41.png?resizew=270)
(1)求证:平面
平面
;
(2)当
时,
与底面
所成角的正弦值为
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e65ac334119ccd6204402a7aba29a55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c4f6f74444b2b7947fc6e35c8d62322.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23f919bd3dde10dbbc076f7ec5149699.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16d65cecaf8a3dc2953f4109c75a981e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07a29c76231ca25d57092f5789bdf115.png)
![](https://img.xkw.com/dksih/QBM/2020/2/9/2395180869443584/2395846742056960/STEM/c0002da49e9d4a6596eae2bff70bca41.png?resizew=270)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ec89c4d9a43c9d4f7e0ddcfe0a9360b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74c34b4b9ce51d89b95bbd427bdf361e.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6743198bc7bc14eaabf17d6ee7773c48.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db54223bb3fc2fe2497213a4d1f94827.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0385df6c7f8ee7ab503b6ed35933695b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf31876698721a199c7c53c6b320aa86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/324a1792318a3528772781fac2b4d2e4.png)
更新时间:2020-02-10 09:05:35
|
相似题推荐
【推荐1】在如图所示的直三棱柱
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.
平面
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(2)求三棱锥
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【推荐2】如图,在四面体
中,
,点
是
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在线段
上,且
.
![](https://img.xkw.com/dksih/QBM/2014/9/15/1571853775446016/1571853781057536/STEM/3fc8a4a257c84cf79e3185674f21220a.png?resizew=163)
(1)若
平面
,求实数
的值;
(2)求证:平面
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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![](https://img.xkw.com/dksih/QBM/2014/9/15/1571853775446016/1571853781057536/STEM/3fc8a4a257c84cf79e3185674f21220a.png?resizew=163)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57f9d682e5d3cc8573574d8d11636758.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7abd284f76d9f5769bc189508ce2572b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c309e58bf083bad13abd549720a63a22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e649e04994df61bf49c1c6599c3e7530.png)
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【推荐1】如图,在四棱锥
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,
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,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/2/c848dfe6-9fb2-400a-8d08-9bd82aaeb7f9.png?resizew=169)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45acdbac251ca6b76a166c1242e71df9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f04c222223dae9ef27d4c132534d9848.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
(2)若直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8e1f118774f4f4bd15ed7dd43776be4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
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【推荐2】如图,在三棱锥
中,
,
,
,
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![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/18/e099007a-a2aa-4f1d-b6eb-7199a8c57c84.png?resizew=144)
(1)求二面角
的余弦值;
(2)在直线AB上是否存在点M,使得PM与平面PAD所成角的正弦值为
,若存在,求出点M的位置;若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/209acf15985d1ea1ad86fc4a37e38c0b.png)
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![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/18/e099007a-a2aa-4f1d-b6eb-7199a8c57c84.png?resizew=144)
(1)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad6a0cee8226e82cc57916e10d533369.png)
(2)在直线AB上是否存在点M,使得PM与平面PAD所成角的正弦值为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e6486784415f3537c9a13556c05d893.png)
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【推荐1】如图,在三棱柱
中,四边形
是长方形,
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,
,
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![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/11/b19aa656-9400-44fe-8a73-e9afb2e82d97.png?resizew=145)
证明:平面
平面
;
若
,
,
,求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ede6a60cad0e0b58e1549fda6e085719.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24d5a373112efbf36f1989234a4c19aa.png)
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![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/11/b19aa656-9400-44fe-8a73-e9afb2e82d97.png?resizew=145)
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【推荐2】如图,在四棱锥
中,
,四边形
是菱形,
,
,
,
是棱
上的中点.
(1)求三棱锥
的体积;
(2)求平面
与平面
夹角的余弦值.
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(1)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/50ea1efba56e577f2a289b4be22bbc73.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c66d99a6a8415ddad22bbed33b64cfb.png)
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