如图,在四棱锥
中,底面
为直角梯形,
,
和
均为等边三角形,且平面
平面
,点
为
的中点.
![](https://img.xkw.com/dksih/QBM/2018/2/11/1879880909725696/1881700494729216/STEM/3c1f896e08854a33a908e9b0b369f057.png?resizew=134)
(1)求证:
平面
;
(2)求平面
与平面
所成的锐二面角的余弦值.
![](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/cb67b93de1defce9bc51fde4b7e05621.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecc34a42e6838de94da6dc08e0b578cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a1fc2305fd371a1ff1f91cd834140e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19ad6a0124359e8b9f7649cf0bff51ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4739afd7311501e948aa4e1e5c1cb17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://img.xkw.com/dksih/QBM/2018/2/11/1879880909725696/1881700494729216/STEM/3c1f896e08854a33a908e9b0b369f057.png?resizew=134)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31c34b18525831f3eda7bb90be0199b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/218054144a13435580cd132b9459546c.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
更新时间:2017-09-04 08:15:50
|
相似题推荐
解答题
|
适中
(0.65)
【推荐1】如图,在直四棱柱
中,底面
为菱形,
,
;
为
中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/6/0cb81ff1-d494-43da-b46f-2bf5e7fcb6ab.png?resizew=162)
(1)证明:
面
;
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e1f4f255d191786f7d330d278868c2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9365371148e79be4c7324bc424e1cc83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fe734023d4e70010a6b2cc3267cb86e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/6/0cb81ff1-d494-43da-b46f-2bf5e7fcb6ab.png?resizew=162)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/02667cd162e00ad8364e4c6e4aec524c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46e2da608b66c9aee03e2503388ba4fd.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed047df6b180b77f6653b277c174a551.png)
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名校
【推荐2】如图,在四棱锥
中,
平面
,
,且
平分
,
为
的中点,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/19/b7ffa9fe-dad0-4a44-b619-3329bcd460f5.png?resizew=163)
(1)证明![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
平面
;
(2)求直线
与平面
所成的角的正切值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cdb2dd10731b99c0f4f89ee957f8a239.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d97dc3b752832906de41447bb58a341.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3981e7286d41960daf4e110c1c84e03a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/633bf2de732ae51fc06ef3d559915da0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a9b1d39efca82ac0f3bf059e49b103.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/19/b7ffa9fe-dad0-4a44-b619-3329bcd460f5.png?resizew=163)
(1)证明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb31ef428bd9de9bc875b343feded3c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f571a1aac46c6d0cf440c0ec2846bf9.png)
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(0.65)
解题方法
【推荐3】在如图多面体中,
底面
,
,
,G是BC的中点.
![](https://img.xkw.com/dksih/QBM/2020/7/13/2505207786323968/2506548108853248/STEM/e3add40f-edf8-441b-9585-c9772afc5fa1.png)
(1)
平面
;
(2)
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1e0bd4b30dc777ac9da80f6baa3eb31.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a6480f384476190883f06c0289c7519.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fef5ff8e198b340ab2b5a2abe48e0e72.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cba7d2ce69e27c561fd17d9eceb3a77.png)
![](https://img.xkw.com/dksih/QBM/2020/7/13/2505207786323968/2506548108853248/STEM/e3add40f-edf8-441b-9585-c9772afc5fa1.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/307807ee10071bafbe922eb18d2517d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c96bc9a285172c48e4726ee6492670ef.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1d0df73a49d4348a5c1e3aaa149cc8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ae8768996ca9a0f2c5d9a19abbd54df.png)
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【推荐1】如图1,在边长为
等边
中,点D、E分别为边
、
上的中点.将
沿
翻折到
的位置并使得平面
平面
,连接
,
得到图2,点N为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/24/c03d25b0-e600-4419-82bb-135c4be8189e.png?resizew=326)
(1)证明:
平面
;
(2)求二面角
的余弦值大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf469ccdd5d3ea978357af1d60fe4022.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f93f2a12dcd9fd0d4500b26031924404.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88c9167bb3dd30117b6c24fee896a9cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e5c62f22d7afc5627fcb86599faa8e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c884b508394b3ab50734b584d9ec783c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c884b508394b3ab50734b584d9ec783c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/24/c03d25b0-e600-4419-82bb-135c4be8189e.png?resizew=326)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/752dc3cc77f0d0ec4a1d0981970410a0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9af29254fe60a392c249c5791279e9c8.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6306a5c48c6a2b30eb0c6548c1b99ee.png)
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【推荐2】已知四棱锥
,底面
为菱形,
,侧面
为等边三角形且垂直于底面.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/15/1520c082-0996-4288-a347-411502118044.png?resizew=239)
(1)求证:
;
(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/7bb8fb552b9e21dbaba74d11aa747790.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/15/1520c082-0996-4288-a347-411502118044.png?resizew=239)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cdfa54114f04a75b8c96165b3718ed7f.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b33b7213d99a817bff19bcf740a0697c.png)
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(0.65)
解题方法
【推荐1】如图,在平面四边形
中,
且
,分别将
、
沿直线
翻转为
、
(
,
不重合),连结
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/14/64d2924d-b5d5-4a0c-85b5-9cba202779c2.png?resizew=169)
(1)求证:
;
(2)若
,
,点
在平面
内的正投影
为
的重心,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a16dc02090b6e9263555061f14fbc8c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bd6a2b112facda441f4e34bf5c145fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab2a2834d80ff574e79eae8ca8d4e94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73636989e83905f8800a865c2b608c43.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b96715995549e5e48494101570bb3bb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b229af07819fdf0bf9b391123eebdf5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c672f693a7e75a7bae4936dcb1920430.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/14/64d2924d-b5d5-4a0c-85b5-9cba202779c2.png?resizew=169)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ef9500289a895ad4d69f113a11e7525.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f08273d339dc5ddbb89aa67bb8205e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d768ffd5bf75080e8ff5ce6b472c0cc0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab2a2834d80ff574e79eae8ca8d4e94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/445b51117626fbd3373e32acc514c64b.png)
您最近一年使用:0次
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【推荐2】如图,四边形
是正方形,
平面
,
,
,
,
,
分别为
,
,
的中点.
(1)求证:
平面
;
(2)求平面
与平面
所成锐二面角的大小;
(3)在线段
上是否存在一点
,使直线
与直线
所成的角为
?若存在,求出线段
的长;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed04b01505bbd8a4ac0bc12e46f23bf6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48cccf96caf5825e81a38c0358227fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f45ea9d4410e9926c592fa0a9dfac97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccaee8f228ff24e7c89879bb5b999cf2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/29/d5680db1-10f6-4fec-90af-1344bb1f611e.png?resizew=165)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63a779876cdfb2c489ad0eaed0f73e6b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/425bb0d1c21eb4448dbbe9a41efa7538.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1828e73ec5e00f95aa11ff74c703a5c1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
(3)在线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2273ae1ee99cec9c1304323bc9ebf75f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d88591679796c52024d11c4de641bdb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/892909e49156f7dcc0650fcd65243877.png)
您最近一年使用:0次