如图甲,直角梯形
中,
,
,点
、
分别在
,
上,且
,
,
,
,现将梯形
沿
折起,使平面
与平面
垂直(如图乙).
(Ⅰ)求证:
平面
;
(Ⅱ)当
的长为何值时,
二面角
的大小为
?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f79863ffcfa63117ca6741b20a48e69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2324805c5dfe2a35787bc3af840586ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f479d987bc7abd828c64f9dc745836ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c54b729996e63624d896ac0409083c28.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef0402dd5ae3db10281f9f1e11738bcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d8511eeface9029eeaeaf60ec2c722d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b80a0e428cb894bfd09a6129a73ea4ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9238757804254960bc40fa9d87065559.png)
(Ⅰ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/307807ee10071bafbe922eb18d2517d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2f2ff8aae606dbc83ed086be4405c75.png)
(Ⅱ)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3533837e3d08c461dea031a44e5424d.png)
二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/894a171f4b92c437544ba372348f41c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/996bf3d35b6763cbc1a423b13a9df2dd.png)
![](https://img.xkw.com/dksih/QBM/2016/4/7/1572568923701248/1572568930066432/STEM/fec3ca1f-1550-4031-90ad-dc2c688ac597.png?resizew=427)
2010·重庆·一模 查看更多[7]
(已下线)2010年重庆市重点中学高考模拟试卷(已下线)2011届贵州省遵义四中7校高三联考理数试题(已下线)2012届新课标高三下学期二轮复习综合验收(5)理科数学试卷2016届四川省成都七中高三3月第一周周末练习数学试卷宁夏银川一中2020-2021学年高二上学期期末考试数学(理)试题(已下线)专题07 空间向量与立体几何-【备战高考】2021年高三数学高考复习刷题宝典(解答题专练)(已下线)专题12 选择性必修第一册综合练习-(新教材)2020-2021学年高二数学单元复习(人教A版选择性必修第一册)
更新时间:2016-12-04 05:02:35
|
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解答题-问答题
|
适中
(0.65)
解题方法
【推荐1】如图,四棱锥
中,底面
是边长为3的菱形,
,
面
,且
,
在棱
上,且
,
在棱
上.
![](https://img.xkw.com/dksih/QBM/2016/8/8/1572967802118144/1572967808262144/STEM/e3f318325c7c4ba69b636355dde3c0e8.png?resizew=239)
(1)若
面
,求
的值;
(2)求二面角
的余弦值.
![](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/e075468e7fb0bf30229aec01a7205977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/491c3a4f72b84ebadd28b90711435adc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0cee0f36dc452e58086832c0152b641.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://img.xkw.com/dksih/QBM/2016/8/8/1572967802118144/1572967808262144/STEM/e3f318325c7c4ba69b636355dde3c0e8.png?resizew=239)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/932a04304f2d4975955d4baabb2deeea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ae8768996ca9a0f2c5d9a19abbd54df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e78bb5559273572b7687802efd2dac7.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d243d9a135116a6749d586fd5b95ec73.png)
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解答题-问答题
|
适中
(0.64)
【推荐2】如图,已知四棱锥
的底面
是正方形,侧棱
底面
.
![](https://img.xkw.com/dksih/QBM/2016/1/13/1572433164615680/1572433170612224/STEM/4c3eafc7d6ee4763b39ec1d57f59a6c1.png)
(1)若
,
是
的中点.证明:
平面
;
(2)若二面角
的余弦值为
,试求
的值.
![](https://img.xkw.com/dksih/QBM/2016/1/13/1572433164615680/1572433170612224/STEM/13dc5ab55742408f820b8c81829049b4.png)
![](https://img.xkw.com/dksih/QBM/2016/1/13/1572433164615680/1572433170612224/STEM/d5449102fa8e47479b30d2e2c8ba47e8.png)
![](https://img.xkw.com/dksih/QBM/2016/1/13/1572433164615680/1572433170612224/STEM/3ac4488fda7a49079a9482ad2fc23ecf.png)
![](https://img.xkw.com/dksih/QBM/2016/1/13/1572433164615680/1572433170612224/STEM/d5449102fa8e47479b30d2e2c8ba47e8.png)
![](https://img.xkw.com/dksih/QBM/2016/1/13/1572433164615680/1572433170612224/STEM/4c3eafc7d6ee4763b39ec1d57f59a6c1.png)
(1)若
![](https://img.xkw.com/dksih/QBM/2016/1/13/1572433164615680/1572433170612224/STEM/92b3af603b2f4ed580114218d251dfc2.png)
![](https://img.xkw.com/dksih/QBM/2016/1/13/1572433164615680/1572433170612224/STEM/683cd53d4c6d4f1e92795231da09d7a8.png)
![](https://img.xkw.com/dksih/QBM/2016/1/13/1572433164615680/1572433170612224/STEM/a5cdc90196bd4f169e84780eca076cfc.png)
![](https://img.xkw.com/dksih/QBM/2016/1/13/1572433164615680/1572433170612224/STEM/58e953e7d10b4f248ba691350d014eae.png)
![](https://img.xkw.com/dksih/QBM/2016/1/13/1572433164615680/1572433170612224/STEM/29a831d3c36743ba8209e4bebea6e549.png)
(2)若二面角
![](https://img.xkw.com/dksih/QBM/2016/1/13/1572433164615680/1572433170612224/STEM/8e733c889468424482919eb3e572f096.png)
![](https://img.xkw.com/dksih/QBM/2016/1/13/1572433164615680/1572433170612224/STEM/99b617f11beb40cbbe4a764c6dc933fb.png)
![](https://img.xkw.com/dksih/QBM/2016/1/13/1572433164615680/1572433170612224/STEM/86f9c1f4d9b44eac95c52765a95dfa9c.png)
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解答题-问答题
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适中
(0.65)
名校
【推荐1】在棱长为2的正方体
中,
分别为棱
和
的中点.
(1)证明:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
平面
;
(2)求异面直线
与
所成的余弦值;
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52041559f8fee18bfa3e2e2ac07c3bfa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22adbc0da438220f9cace11b629d799b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/638537c0a30676c73fea76c80e0f8bd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bb10d645970e5860afd3430957fab6c.png)
(2)求异面直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e72b2e1ff83e95df048745322982451.png)
您最近一年使用:0次
解答题-证明题
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适中
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【推荐2】某建筑物的上层框图如图所示,其上下底面是平行的两正方形,上下底面的中心连线垂直于上下地面,且各侧棱均相等(即为正棱台),经测量得知
,侧棱长为
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/4/7b28e486-08db-4c9b-b922-fcffe281bd16.png?resizew=265)
(1)求证
;
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c1060dbf8c1a85848754e0717799793.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bcf43ba416adeb723cebe4aee6bbe34.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/4/7b28e486-08db-4c9b-b922-fcffe281bd16.png?resizew=265)
(1)求证
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1de5964353beb55c5058b2a431eecaf.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b6ab5a1695a47751d93ec248ee61eaa.png)
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