如图所示,在三棱柱
中,
为正方形,
为菱形,
,平面
平面
.
![](https://img.xkw.com/dksih/QBM/2016/4/29/1572611780354048/1572611786670080/STEM/0cf0e473d2494cafbcb2a6b2bc5a0fd5.png?resizew=200)
(Ⅰ)求证:
;
(Ⅱ)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9edc50f7febbc2d5d8dcdc23a3630a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58cc6184b191e6da43911e701121517e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b51221630159e52bda685680fa684d8c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce04b35c265cc9c48b60204bd2f718ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58cc6184b191e6da43911e701121517e.png)
![](https://img.xkw.com/dksih/QBM/2016/4/29/1572611780354048/1572611786670080/STEM/0cf0e473d2494cafbcb2a6b2bc5a0fd5.png?resizew=200)
(Ⅰ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb81a917e1183890a82885b350b63f14.png)
(Ⅱ)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6dfb64c679bf4a62e5ee092d8885fc09.png)
更新时间:2016-12-04 06:29:46
|
相似题推荐
解答题-问答题
|
适中
(0.64)
【推荐1】如图,四棱锥
中,底面
为平行四边形,
为
的中点,
平面
为
的中点,
,
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0999ac4d13b6c984945376346652d581.png)
![](https://img.xkw.com/dksih/QBM/2015/2/10/1571987097657344/1571987103645696/STEM/6331207d5e8d4b3d942e6152bd707c4d.png?resizew=165)
(1)证明:
平面
;
(2)如果二面角
的正切值为2,求
的值.
![](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/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3e126c16032892966489053f44b9048.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dfaefb10f82b89802bb420b3c41de1bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd7e4e8c2835c4a880cd4430800e1f8c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24dcd50b9f6dba73b160297efd9574c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0999ac4d13b6c984945376346652d581.png)
![](https://img.xkw.com/dksih/QBM/2015/2/10/1571987097657344/1571987103645696/STEM/6331207d5e8d4b3d942e6152bd707c4d.png?resizew=165)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd654221ab95fe241d9e0202443f2609.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
(2)如果二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/698335f4880c7a298f4898c83b6562bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
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解答题-证明题
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适中
(0.64)
【推荐2】如图,在五面体ABCDEF中,四边形ABCD是平行四边形.
![](https://img.xkw.com/dksih/QBM/2015/6/10/1572121164242944/1572121170214912/STEM/6e66593c46a946c9a25f9490f7f35d01.png)
(1)若CF⊥AE,AB⊥AE,求证:平面ABFE⊥平面CDEF;
(2)求证:EF//平面ABCD.
![](https://img.xkw.com/dksih/QBM/2015/6/10/1572121164242944/1572121170214912/STEM/6e66593c46a946c9a25f9490f7f35d01.png)
(1)若CF⊥AE,AB⊥AE,求证:平面ABFE⊥平面CDEF;
(2)求证:EF//平面ABCD.
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解答题-问答题
|
适中
(0.65)
【推荐1】如图,在三棱柱
中,
,
,点
在平而
内的射影为![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/30/539f57db-14cd-4c7e-a2e3-18d941c69b44.png?resizew=162)
(1)证明:四边形
为矩形;
(2)
分别为
与
的中点,点
在线段
上,已知
平面
,求
的值.
(3)求平面
与平面
所成锐二面角的余弦值
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ab4629fbb62d88ec595376f3380e543.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e962da66afb60383679482ef525d8b9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f403ead8fe35d99a686da80d9d38070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dec2a049ae4316eacff4b303b251e770.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/30/539f57db-14cd-4c7e-a2e3-18d941c69b44.png?resizew=162)
(1)证明:四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7831e7a79b57cdc733bc3c042556305.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3cf9b288c48c73463a2f214f02b6952a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6d9718c3feff96850610a6d8cdb746a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06222ee533c2484ab25321a6abbf98cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7935fe3125f247b7bea4f065ce9ad985.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ab8bef0a40c94a55e42a2f7fbb0ae03.png)
(3)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3532749fe129c8718beec37a0fbc5563.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d9a8181f7a7fe7f3fac872ce9534f15.png)
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适中
(0.65)
解题方法
【推荐2】在滨海文化中心有天津滨海科技馆,其建筑有鲜明的后工业风格,如图所示,截取其中一部分抽象出长方体和圆台组合,如图所示,长方体
中,
,圆台下底圆心
为
的中点,直径为2,圆与直线
交于
,圆台上底的圆心
在
上,直径为1.
![](https://img.xkw.com/dksih/QBM/2021/4/23/2705880246927360/2730846585544704/STEM/45b2fb4d77584581b5ffa7988d973437.png?resizew=234)
![](https://img.xkw.com/dksih/QBM/2021/4/23/2705880246927360/2730846585544704/STEM/5d45fccb0ba7472eb5b9f5ed084f1e3a.png?resizew=205)
(1)求
与平面
所成角的正弦值;
(2)求二面角
的余弦值;
(3)圆台上底圆周上是否存在一点
使得
,若存在,求点
到直线
的距离,若不存在则说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2089110ce065e01dc57e38edb840dceb.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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23f919bd3dde10dbbc076f7ec5149699.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://img.xkw.com/dksih/QBM/2021/4/23/2705880246927360/2730846585544704/STEM/45b2fb4d77584581b5ffa7988d973437.png?resizew=234)
![](https://img.xkw.com/dksih/QBM/2021/4/23/2705880246927360/2730846585544704/STEM/5d45fccb0ba7472eb5b9f5ed084f1e3a.png?resizew=205)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88c9f260496ba23993238601a89eca5c.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae190120755c4dd7070df21dd0a90a01.png)
(3)圆台上底圆周上是否存在一点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44b72acd3da8b22454e5d461379f5bde.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
您最近一年使用:0次