名校
1 . 如图,
平面
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/28/a45baf47-c0a1-42ae-af37-c08dab14ea45.png?resizew=161)
(1)求证:
平面
;
(2)若二面角
的余弦值为
,求直线
与平面
所成角的正切值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f4c3f9dd5d0343597a7f58a1989b537.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a572ab3fbf0228c7a32efbf9629c2f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60595898e8028fce7fd88170e4868580.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/28/a45baf47-c0a1-42ae-af37-c08dab14ea45.png?resizew=161)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/063510e3c1fb6a7ccc3b8e3e3c7d660e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a09d9d486b7f91ba933210dd013a7f2c.png)
(2)若二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/147310251a463539f66374c1f452fb67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dac452fbb5ef6dd653e7fbbef639484.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2319a01218514917e446dfc807a625ff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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2022-01-03更新
|
1878次组卷
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3卷引用:吉林省长春市东北师范大学附属中学2021-2022学年高三上学期第三次摸底考试理科数学试题
吉林省长春市东北师范大学附属中学2021-2022学年高三上学期第三次摸底考试理科数学试题(已下线)专题10 立体几何线面位置关系及空间角的计算(练)--第一篇 热点、难点突破篇-《2022年高考数学二轮复习讲练测(浙江专用)》四川省德阳市什邡中学2023-2024学年高二平实班上学期期中数学试题
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2 . 如图1,在
中,
,
分别为
,
的中点,
为
的中点,
,
.将
沿
折起到
的位置,使得平面
平面
,如图2.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/26/8ef76929-4cf4-4d0a-80dc-7c3ef3754c48.png?resizew=354)
(1)求证:
.
(2)求直线
和平面
所成角的正弦值.
(3)线段
上是否存在点
,使得直线
和
所成角的余弦值为
?若存在,求出
的值;若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.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/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0117046e7a37bebe0c7b987a00d2bcb7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e65a3e478bb87d094e3a0af30dd10ae8.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/3aa2a83fed9bf4cb09d84a980452e346.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7b3e7c7845a0ec3cbac709fda131764.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65c42bce098904b241986bb91c65ab33.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/26/8ef76929-4cf4-4d0a-80dc-7c3ef3754c48.png?resizew=354)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e51c4114e94bceb198403c1858b9682.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7935fe3125f247b7bea4f065ce9ad985.png)
(3)线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a261474cc7607d31a6324cb4df9c8896.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c741af321a8ddaf387fa661f3920ad84.png)
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2021-02-02更新
|
2447次组卷
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12卷引用:吉林省延边州2023届高三统考二模数学试题
吉林省延边州2023届高三统考二模数学试题安徽省合肥一中、六中、八中2020-2021学年高二上学期期末理科数学试题安徽省合肥市第六中学2020-2021学年高二上学期期末数学(理)试题天津市南开中学2021届高三下学期统练25数学试题(已下线)专题05 空间向量与立体几何(重点)-2020-2021学年高二数学下学期期末专项复习(北师大版2019选择性必修第一册、第二册)天津市第四十七中学2021-2022学年高二上学期第一次月考数学试题福建省南平市浦城县2021-2022学年高二上学期期中考试数学试题广东省梅州市五华县水寨中学学等五校2022-2023学年高二上学期10月联考数学试题(已下线)专题14 押全国卷(理科)第18题 立体几何广东省梅州市五校(虎山中学、丰顺中学、水寨中学、梅州中学、平远中学)2022-2023学年高二上学期期中联考数学试题天津市南开中学2024届高三上学期统练8数学试题(已下线)第3章 空间向量及其应用 单元综合检测(重点)-2023-2024学年高二数学同步精品课堂(沪教版2020选择性必修第一册)
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3 . 如图,在三棱锥
中,
是边长为4的正三角形,
为
的中点,平面
平面
,二面角
的余弦值为
,三棱锥
的体积为
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/28/730a7d73-3533-407e-ac25-418579ab7259.png?resizew=126)
(1)求证:平面
平面
;
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/891579e7c231584a8e16b8eeff79888e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/661ff55b5ebbadfb600989af3cfce2fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d28c625d7ac6878957facc8274d459c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca67a5b8f69507c8b80379e86f90a8ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ec2524be492bca0d1566bf848066f10.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e468f168f3657d84d44be5eb89a62d8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/891579e7c231584a8e16b8eeff79888e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ee05b3210c8964deef8ff771173d288.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/28/730a7d73-3533-407e-ac25-418579ab7259.png?resizew=126)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d28c625d7ac6878957facc8274d459c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c2898853a3396f0878af9eac934416d.png)
您最近一年使用:0次
2020-07-22更新
|
1462次组卷
|
4卷引用:吉林省梅河口市第五中学2020届高三第六次模拟考试数学(理)试题
名校
解题方法
4 . 设三棱锥
的每个顶点都在球
的球面上,
是面积为
的等边三角形,
,
,且平面
平面
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/22/96255708-36bb-4b7c-8821-0f3aa5185494.png?resizew=176)
(1)确定
的位置(需要说明理由),并证明:平面
平面
.
(2)与侧面
平行的平面
与棱
,
,
分别交于
,
,
,求四面体
的体积的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53502463cc76201000e02df314e58769.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/adbd3e8cf8325999cde03adf845d3dd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/615fc8790237a1b09af51d6bcad6b595.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b10134e7a46e6f6f7cb9d5e2371727d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4aa9084b8fe0fe05c4388d1f835587b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/22/96255708-36bb-4b7c-8821-0f3aa5185494.png?resizew=176)
(1)确定
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7392e9e2da5a0e9ecab0f79992656328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)与侧面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.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/c10f93679abcee21bacd92c3b1552a0e.png)
您最近一年使用:0次
2020-02-18更新
|
890次组卷
|
4卷引用:2020届吉林省实验中学高三第一次检测考试数学(文)试题
2020届吉林省实验中学高三第一次检测考试数学(文)试题2020届吉林省通化市梅河口市第五中学高三上学期期末数学(文)试题(已下线)专题04 立体几何-2020年高三数学(文)3-4月模拟试题汇编(已下线)文科数学-6月大数据精选模拟卷04(新课标Ⅲ卷)(满分冲刺篇)
5 . 如图所示,该几何体是由一个直三棱柱
和一个正四棱锥
组合而成,
,
.
![](https://img.xkw.com/dksih/QBM/2017/4/10/1662899279675392/1663445712797696/STEM/d6ef931e24d1499583611af4b017fdf2.png?resizew=251)
(Ⅰ)证明:平面
平面
;
(Ⅱ)求正四棱锥
的高
,使得二面角
的余弦值是
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/535770901287f244911b42412533d4a9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a47dcb24ffe20e8153e0d113ff8bee3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4934c4df6fd69381832ea14d144364cc.png)
![](https://img.xkw.com/dksih/QBM/2017/4/10/1662899279675392/1663445712797696/STEM/d6ef931e24d1499583611af4b017fdf2.png?resizew=251)
(Ⅰ)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93edc7bb513f40a89173121c8570cd65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/369eb8ad56da7dc1cdb7c43762be4bee.png)
(Ⅱ)求正四棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3eabd5f3a86afe49dcd70571e2b96cfd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a487c0c6c507568d1b4dba0a895fae70.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24c14ff9b66f21c05e52dc3c8908c2df.png)
您最近一年使用:0次
2017-04-11更新
|
2111次组卷
|
13卷引用:吉林省松原市实验高级中学等三校2016届高三下学期联合模拟考试理数试题
吉林省松原市实验高级中学等三校2016届高三下学期联合模拟考试理数试题2016届吉林省东北师大附中高三三校联考理科数学试卷2017届湖南省长郡中学、衡阳八中等十三校重点中学高三第二次联考理科数学试卷河北省衡水中学2018届高三上学期八模考试数学(理)试题湖北省襄阳第四中学2018届高三8月月考数学试题2018届高三数学训练题(56):向量法求解立体几何问题人教A版(2019) 选择性必修第一册 必杀技 模块综合测试人教B版(2019) 选择性必修第一册 必杀技 模块综合测试江苏省南京市2020-2021学年高二上学期期中模拟数学试题安徽省滁州市定远县重点中学2020-2021学年高二上学期10月月考数学(理)试题安徽省滁州市定远县民族中学2020-2021学年高二上学期11月月考数学(理)试题江苏省南通市通州高级中学2020-2021学年高三上学期第五次阶段性测试数学试题陕西省西安市铁一中学2023-2024学年高二上学期期中数学试题
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6 . 如图所示,四棱锥
的底面是梯形,且
,
平面
,
是
中点,
.
![](https://img.xkw.com/dksih/QBM/2016/7/12/1572913435418624/1572913441038336/STEM/31381705-a1e7-4634-afe2-ce70a179c2b8.png?resizew=178)
(Ⅰ)求证:
平面
;
(Ⅱ)若
,
,求直线
与平面
所成角的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f79863ffcfa63117ca6741b20a48e69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21f9157fce2a8339d281178c7c0bccbe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b41b89ccb8296f8195f84832995d52dd.png)
![](https://img.xkw.com/dksih/QBM/2016/7/12/1572913435418624/1572913441038336/STEM/31381705-a1e7-4634-afe2-ce70a179c2b8.png?resizew=178)
(Ⅰ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44b190c8d3d7d7d0e6e959e8a52eae90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
(Ⅱ)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df003447e98fd5ba9badd42177f345db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/218054144a13435580cd132b9459546c.png)
您最近一年使用:0次
2016-12-04更新
|
1396次组卷
|
5卷引用:2016届吉林省毓文中学高三高考热身考试理科数学试卷
7 . 如图,在多面体ABCDEF中,正方形
与梯形
所在平面互相
垂直,已知
,
,
.
![](https://img.xkw.com/dksih/QBM/2015/7/9/1572175742091264/1572175748251648/STEM/ce3bf7a6662f43a88715b7f4a4d0526d.png)
(Ⅰ)求证:
平面
;
(Ⅱ)求直线
与平面
所成的角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ecc1cb55a57dde481f8dd07ab150676.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
垂直,已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/899389400366ef131e169847a4286301.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d262480ffb55b7617f44b63f130c154a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/833cfda415649b832cc136caed392753.png)
![](https://img.xkw.com/dksih/QBM/2015/7/9/1572175742091264/1572175748251648/STEM/ce3bf7a6662f43a88715b7f4a4d0526d.png)
(Ⅰ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc3719c11b0b0ae54d43d6f45fe7b1f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
(Ⅱ)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc3719c11b0b0ae54d43d6f45fe7b1f8.png)
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8 . 如图,在三棱柱
-中,
,
,
,
在底面
的射影为
的中点,
为
的中点.
![](https://img.xkw.com/dksih/QBM/2015/6/24/1572143291596800/1572143297462272/STEM/ca9589b5-fb94-4b05-adce-46a75f3aa737.png?resizew=214)
(1)证明:
D
平面
;
(2)求二面角
-BD-
的平面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f8e9ec412ea0355e4e5cd06c60e5fee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c3e9ef3e849788645552cfb0735d987.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1880586c33da315e49ccb6e2d531c6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18722354086c42e62334983fc50eb6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.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/56f7ba05c54b3de1f4378f7c8eb58328.png)
![](https://img.xkw.com/dksih/QBM/2015/6/24/1572143291596800/1572143297462272/STEM/ca9589b5-fb94-4b05-adce-46a75f3aa737.png?resizew=214)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18722354086c42e62334983fc50eb6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1633988fd62a652de726ee92a917b52d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/02831149d08a249bb36f006020a76b86.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18722354086c42e62334983fc50eb6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97c01fdc7bc471af0b264a04aef0823e.png)
您最近一年使用:0次
2016-12-03更新
|
6208次组卷
|
13卷引用:2016届吉林四平一中高三五模理科数学试卷
2016届吉林四平一中高三五模理科数学试卷2015年全国普通高等学校招生统一考试理科数学(浙江卷)广东省华南师范大学附属中学2017-2018学年高二10月月考数学(理)试题第二章 高考链接(二)(已下线)专题12 点线面的位置关系与空间的角-2021年浙江省高考数学命题规律大揭秘【学科网名师堂】辽宁省沈阳市第二十中学2021-2022学年高三上学期期末数学试题浙江省北斗联盟2021-2022学年高二下学期期中联考数学试题广东省五校(广州市第二中学等)2021-2022学年高一下学期期末联考数学试题(已下线)期末复习07 空间几何线面、面面垂直-期末专项复习河北省唐县第一中学2022-2023学年高二下学期3月月考数学试题(已下线)高二上学期期中【常考60题考点专练】(选修一全部内容)-2022-2023学年高二数学考试满分全攻略(人教A版2019选修第一册)(已下线)第七章 应用空间向量解立体几何问题拓展 专题一 立体几何非常规建系问题 微点1 立体几何非常规建系问题(一)【培优版】(已下线)专题23 立体几何解答题(理科)-2
9 . 如图,在四棱锥
中,
,
是直角梯形,
,
为线段
上一点
![](https://img.xkw.com/dksih/QBM/2016/6/29/1572842943766528/1572842949304320/STEM/c0e4e6bbe99841ae876b1dc8186a7b6e.png)
(1)求证:
;
(2)若二面角
的余弦值为
,求
的值
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6153163fecdf3f410411048428ccaef5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/151aa5df0641c332eef99dfcb3fc5ec4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa9ba706fb8404519ea5b8555c920777.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/321fe59568e9a79f67e7e23aea636a0c.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/2016/6/29/1572842943766528/1572842949304320/STEM/c0e4e6bbe99841ae876b1dc8186a7b6e.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e19a5a13f5c59bf3acb85b096f926023.png)
(2)若二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccc70dc2132d02d3e2c36452ddbc45e0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1174142f3bba761585b6bc2653009b36.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7fb4402e082c123111c12fc6cc3acbc9.png)
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