如图,在长方体ABCD﹣A1B1C1D1中 AD=AA1=1,AB=2
(1)证明:当点E在棱AB移动时,D1E⊥A1D;
(2)(理)在棱AB上是否存在点E,使二面角D1﹣EC﹣D的平面角为
?若存在,求出AE的长;若不存在,请说明理由.
(文)在棱AB上是否存在点E使CE⊥面D1DE,若存在,求出AE的长;若不存在,请说明理由.
(1)证明:当点E在棱AB移动时,D1E⊥A1D;
(2)(理)在棱AB上是否存在点E,使二面角D1﹣EC﹣D的平面角为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c67d01e61dc0042e67b5e8ec8e727c22.png)
(文)在棱AB上是否存在点E使CE⊥面D1DE,若存在,求出AE的长;若不存在,请说明理由.
![](https://img.xkw.com/dksih/QBM/2011/11/25/1570363774468096/1570363780022272/STEM/b018bb46-1703-4a77-8728-ea78121f8a61.png?resizew=299)
11-12高二上·广东·期中 查看更多[1]
(已下线)2011年广东省执信中学高二上学期期中考试数学
更新时间:2016-12-01 02:16:12
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解答题-问答题
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适中
(0.65)
解题方法
【推荐1】如图所示的三棱柱
中,
,
.
![](https://img.xkw.com/dksih/QBM/2016/7/27/1572944464273408/1572944470704128/STEM/f7155c68d57a4a34a075ad717c9a4363.png?resizew=295)
(1)证明:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/968b886a9f161fdcab1e08cba8ece5d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1633988fd62a652de726ee92a917b52d.png)
;
(2)若
,
,求三棱柱
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc6a1a01fdb186620b7939c789fb8bf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d191901eb333651ffc204104d632162.png)
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![](https://img.xkw.com/dksih/QBM/2016/7/27/1572944464273408/1572944470704128/STEM/f7155c68d57a4a34a075ad717c9a4363.png?resizew=295)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/968b886a9f161fdcab1e08cba8ece5d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1633988fd62a652de726ee92a917b52d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74a2ddd96a0b3d640dbae6767ac46725.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a5a89ba08524c9b8283d73aacced38b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ea507a45c8ed33f1ef33e13d28c744e.png)
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解答题-问答题
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适中
(0.65)
【推荐2】在三棱锥
中,平面
平面ABC,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/54dae05e-0b96-4dbd-b416-e0ce163296ef.png?resizew=217)
(Ⅰ)证明:
平面ABC;
(Ⅱ)已知Q,M,N分别为线段PA、PB、BC的中点,求直线MN与平面QAC所成角的正弦值.
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d077f6da8b2c00b152d4679aa2ed7f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83d6b08ffdd8b042a78cf6b569210f75.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/54dae05e-0b96-4dbd-b416-e0ce163296ef.png?resizew=217)
(Ⅰ)证明:
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(Ⅱ)已知Q,M,N分别为线段PA、PB、BC的中点,求直线MN与平面QAC所成角的正弦值.
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解答题-问答题
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适中
(0.65)
解题方法
【推荐1】如图,在四棱锥
中,
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,四边形
是菱形,点
在线段
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![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/23/4ea0fb8d-0dc6-4775-a84d-bc3063d02fb7.png?resizew=146)
(1)证明:平面
平面
;
(2)若
,二面角
的余弦值为
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.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/411b38a18046fea8e9fab1f9f9b80a5f.png)
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(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e54cf75bbfc9db93d27937c8b8e977b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
(2)若
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1069d514c3c32aeabd274475ee209ed6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af6ddf31b7d9225a4239883af72d153b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b866f6ce2acd514c517a886d70d23de.png)
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名校
【推荐2】如图所示,在四棱锥
中,底面ABCD为直角梯形,
,
,
,点E为AD的中点,
,
平面ABCD,且
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/20/74591e51-9ddd-42c1-91d5-adcffad16c8e.png?resizew=196)
(1)求证:
;
(2)线段PC上是否存在一点F,使二面角
的余弦值是
?若存在,请找出点F的位置;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
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![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/20/74591e51-9ddd-42c1-91d5-adcffad16c8e.png?resizew=196)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e4125524caac016727c80d2722c5ba3.png)
(2)线段PC上是否存在一点F,使二面角
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83303d3784492506fc44f2b4d6b07bc1.png)
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