已知三棱锥
中,
,如图.
![](https://img.xkw.com/dksih/QBM/2017/5/6/1681345989181440/1682049103839232/STEM/ffd8bf9ce797465099e3dd3c930ea93b.png?resizew=160)
(Ⅰ)请在答题卡第18题图中作平面
交
于
点,交
于
点,并且平面
(说明作法及理由);
(Ⅱ)在满足(Ⅰ)的前提下,又有
,求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67f207ea20f21ecde2abbfe27f4c94c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01f0e90bbd84700a3b724ae586f61e7a.png)
![](https://img.xkw.com/dksih/QBM/2017/5/6/1681345989181440/1682049103839232/STEM/ffd8bf9ce797465099e3dd3c930ea93b.png?resizew=160)
(Ⅰ)请在答题卡第18题图中作平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9be269b74e98fe1b863bc0e99bd70d6f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71087225aa7cf4f791ac1925c34e38e1.png)
(Ⅱ)在满足(Ⅰ)的前提下,又有
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/51b2ae9462972cfee8ec8d50a97f352b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/314a608f5e040d4bfb18e757e5bc587d.png)
更新时间:2017-05-07 21:20:34
|
相似题推荐
解答题-证明题
|
适中
(0.65)
解题方法
【推荐1】如图,四棱锥P-ABCD的底面ABCD是边长为4的正方形,平面PAD⊥平面ABCD,
是以PA为斜边的等腰直角三角形,PA=
,E,F分别是棱PA,PC的中点,M是棱BC上一点.
![](https://img.xkw.com/dksih/QBM/2022/1/25/2902193765310464/2918165220483072/STEM/2921ea7e-a6f4-4c77-8f11-83602464aa1e.png?resizew=167)
(1)求证:平面DEM⊥平面PAB;
(2)若直线MF与平面ABCD所成角的正切值为
,求锐二面角E-DM-F的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55a675310c8ba418e5a59beb7317e21e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e2031d209711b058f3d278ede3c1d33.png)
![](https://img.xkw.com/dksih/QBM/2022/1/25/2902193765310464/2918165220483072/STEM/2921ea7e-a6f4-4c77-8f11-83602464aa1e.png?resizew=167)
(1)求证:平面DEM⊥平面PAB;
(2)若直线MF与平面ABCD所成角的正切值为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d5989c84e320b504511f23eeb6e7357.png)
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【推荐2】如图,在四面体
中,底面ABC是边长为1的正三角形,
,点P在底面ABC上的射影为H,
,二面角
的正切值为
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/3/b163ccc3-5d33-4632-973d-143b3937f0da.png?resizew=146)
(1)求证:
;
(2)求异面直线PC与AB所成角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d975f472e1663622e2b7629a3f5ff95.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97145e11dfb0e127164187f11288e6b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10f7a0ab16cbb95691b3d80334a91401.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2967337e3fcb228dded64ab0c41a17e0.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/3/b163ccc3-5d33-4632-973d-143b3937f0da.png?resizew=146)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a15a004f7d47ed595f063e60075223a.png)
(2)求异面直线PC与AB所成角的余弦值.
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解题方法
【推荐1】如图,在几何体
中,平面
平面
,
.四边形
为矩形.在四边形
中,
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/30/b13e53aa-d593-4569-96d3-07db49f03cb4.png?resizew=198)
(1)点
在线段
上,且
,是否存在实数
,使得
?若存在,求出
的值;若不存在,请说明理由.
(2)点
在线段
上,求直线
与平面
所成角的正弦值的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9165d9bfbb0f0d19eb482c2a4c1b29b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb5a68a008a22d5a8cea5fe8dcf31e10.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/292db5a9c6f1f948dc62370d41f73b4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b32c05247f6998d7a70d31d13be4148c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6dceb5cc71fc50f20649f6b9535fd914.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9060f03b9ee41d70d135b1e1a8902ce9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc01b1ea3c7efd39d1454d408040d74b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/30/b13e53aa-d593-4569-96d3-07db49f03cb4.png?resizew=198)
(1)点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e45af6c24f1616dbeaecd92e4fdfedf9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1100379a4385b9ce064847bc21760adc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df55452b4b5fcdcb71f713b736f8b9e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1100379a4385b9ce064847bc21760adc.png)
(2)点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cdba1337ec85fa9722cb4b320a82ae6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09afc70f448545336304333d5b5658b.png)
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解答题-证明题
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(0.65)
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解题方法
【推荐2】已知四棱锥
的正视图是一个底边长为4腰长为3的等腰三角形,图1、图2分别是四棱锥
的侧视图和俯视图.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/4/3502211a-a9aa-4176-b110-49efd58466c6.png?resizew=546)
(1)求证:
;
(2)求四棱锥
的体积及侧面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/4/3502211a-a9aa-4176-b110-49efd58466c6.png?resizew=546)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecf6c62979a7aa534a191d8387a741e8.png)
(2)求四棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
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适中
(0.65)
【推荐3】如图1,在边长为
的正方形
中,点
分别是边
和
的中点,将
沿
翻折到
,连结
,如图2.
(1)证明:
;
(2)当平面
平面
时,求平面
与平面
夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2967337e3fcb228dded64ab0c41a17e0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7789a500686c7a73770404ead6af0590.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7f9fba8a4098c1a0515286eb8d616dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fb62dd4766d11cfec3aee092b99e40c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6491c0f5bbef1eb8b588d550477096e6.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/30/1a3b3887-ee4d-469a-adae-e9be7ba9ba02.png?resizew=334)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e4ece75fe9b8555909be5a00d2b7af0.png)
(2)当平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/392469b357b12b998528499929366c02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0760712e3e2ea02b755b751e760d0c55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7476d9918d30619e35cedf37fb6c5842.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14005a5b56ca60089aba722208649104.png)
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