名校
1 . 如图1,在平行四边形
中,
=60°,
,
,
,
分别为
,
的中点,现把平行四边形
沿
折起如图2所示,连接
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/3/b8e39710-99eb-4ef5-abe1-9a672673aa4c.png?resizew=396)
(1)求证:
;
(2)若
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/883732ae71bfed76e07732ec709f4653.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4b5d693c4f0c4d0e6c0c810e7d464b0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92535536bd3c2761724fd058427f95a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1241216f3c1cb5e73043dd1037f556d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/883732ae71bfed76e07732ec709f4653.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7f6f93171329d508d491143b9d71f7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa6cb992b6faad4744f85d73a3b76dd5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a56f2e56229a722d1f40d74d3967a3d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/3/b8e39710-99eb-4ef5-abe1-9a672673aa4c.png?resizew=396)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82c2b3adb41e8965f553da2e5086a751.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24a677b42f8b427b21924a559b90141d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c44507c93f6180afd1697d2fa5a5c741.png)
您最近一年使用:0次
2021-06-15更新
|
1645次组卷
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12卷引用:广西南宁二中2020届高三4月开学考试理数试题
广西南宁二中2020届高三4月开学考试理数试题2016届福建福州市高三上学期期末数学(理)试卷2017届河南南阳一中高三理上学期月考四数学试卷宁夏石嘴山市第三中学2017届高三下学期第三次模拟考试数学(理)试题河南省南阳市2018届高三期终质量评估数学(理)试题四川省成都市实验外国语学校2020届高三(高2017级)数学模拟(三)理试题(已下线)专题19 立体几何综合-2020年高考数学(理)母题题源解密(全国Ⅲ专版)湖北省武汉一中2021届高三下学期二模数学试题广东省广州市广州大学附属中学2021-2022学年高二上学期第一次月考数学试题广东省真光中学2021-2022学年高二上学期10月月考数学试题(已下线)2022年高考考前20天终极冲刺攻略(三)【理科数学】 (5月27日)2023版 北师大版(2019) 选修第一册 突围者 第三章 专项拓展训练3 用空间向量解决折叠问题
名校
2 . 如图,在四棱锥
中,底面
中
,
,侧面
平面
,且
,点
在棱
上,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/22/29abe2ad-3248-4320-95f7-063435bc37e4.png?resizew=198)
(Ⅰ)证明:
平面
;
(Ⅱ)求二面角
的余弦值
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80c753cb1eb73fd8d136d00462970797.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3402ea855e2ae2dcd98f607bef4fdd6c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed5f0cfc1049f84a04c81bd213afb8d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4770a1f98495ff85859bc6508d6d5a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76b54647a7c34d1046c8d6c198d3654d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/22/29abe2ad-3248-4320-95f7-063435bc37e4.png?resizew=198)
(Ⅰ)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11d27ff0b39832f094ec51e28721d739.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bc46688d8723cf2003fc25890265200.png)
(Ⅱ)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/135a12aa48eb33bf5116662e0f9f0799.png)
您最近一年使用:0次
2020-11-24更新
|
1029次组卷
|
4卷引用:广西南宁市2021届高三12月特训测试理科数学试题
广西南宁市2021届高三12月特训测试理科数学试题天一大联考(河北广东全国新高考)2020—2021 学年高中毕业班阶段性测试(二)(已下线)第八单元 立体几何 (A卷 基础过关检测)-2021年高考数学(理)一轮复习单元滚动双测卷内蒙古赤峰红旗中学2021-2022学年下学期高二年级期中考试数学试题
名校
解题方法
3 . 在棱长为
的正方体
中,
是底面
的中点,
,
分别是
,
的中点,那么异面直线
和
所成的角的余弦值等于( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/212f4416ce8fcd69b531ceda6f6ebfbc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.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/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a299d2b999568e80be8005565ba209a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3e54ad0870e36726547ee79f6e093be.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/16/74c4f8b3-3f64-448d-91ce-159f008228fd.png?resizew=169)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次
2020-10-23更新
|
1310次组卷
|
5卷引用:天津市静海区大邱庄中学2020-2021学年高二上学期第一次月考数学试题
4 . 如图,在直三棱柱
中,点
、
分别为
和
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/27/dc67479f-01e4-4abd-8307-1cf201bdd9ea.png?resizew=201)
(1)证明:
平面
;
(2)若
,
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.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/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56f7ba05c54b3de1f4378f7c8eb58328.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/27/dc67479f-01e4-4abd-8307-1cf201bdd9ea.png?resizew=201)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/063510e3c1fb6a7ccc3b8e3e3c7d660e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14d355b4c58b4e883b9e65cc6da8622e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98e384e0ffc3d599303b77ee2a12221e.png)
您最近一年使用:0次
2020-09-25更新
|
932次组卷
|
3卷引用:广西玉林市田家炳中学2020-2021学年高二上学期质量检测数学试题
名校
解题方法
5 . 如图,直四棱柱
的底面是菱形,
,
,M是
的中点,则异面直线
与
所成角的余弦值为( )
![](https://img.xkw.com/dksih/QBM/2020/7/9/2502381914177536/2503478292144128/STEM/1b9bde527fdc44508d37627904df903a.png?resizew=186)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4339a40ae9d1947ec3a4b3e2fa3a16cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f945a69cf7e8213e50622125cde652f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9399c9a2a31b0e3165aea2d6ccc4f7c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7f6f93171329d508d491143b9d71f7b.png)
![](https://img.xkw.com/dksih/QBM/2020/7/9/2502381914177536/2503478292144128/STEM/1b9bde527fdc44508d37627904df903a.png?resizew=186)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次
2020-07-11更新
|
2649次组卷
|
18卷引用:广西百色市平果县第二中学2020-2021学年高二10月月考数学试题
广西百色市平果县第二中学2020-2021学年高二10月月考数学试题黑龙江省哈尔滨师范大学附属中学2020届高三下学期第三次模拟数学(理)试题东北三省三校(哈师大附中、东北师大附中、辽宁省实验中学)2020届高三高考数学(理科)三模试题湖北省武汉襄阳荆门宜昌四地六校考试联盟2020-2021学年高三上学期起点联考数学试题(已下线)第36讲 空间向量的应用-2021年新高考数学一轮专题复习(新高考专版)黑龙江省大庆市第四中学2019-2020学年高一下学期第三次检测数学(理)试题天津市滨海新区塘沽一中2020-2021学年高二上学期期中模拟卷(二)数学试题(已下线)第30练 空间点、线、面的位置关系-2021年高考数学(理)一轮复习小题必刷湖北省华中师大一附中等六校2020-2021学年高三上学期联考数学试题(已下线)1.4.2 空间向量的应用(二)(精练)-2020-2021学年一隅三反系列之高二数学新教材选择性必修第一册(人教版A版)天津市西青区杨柳青第一中学2020-2021学年高二上学期9月月考数学试题(已下线)专练02 空间向量的数量积运算-2021-2022学年高二数学上册同步课后专练(人版A版选择性必修第一册)天津市滨海新区塘沽一中2021-2022学年高二上学期第一次统练数学试题吉林省汪清县汪清第四中学2021-2022学年高二上学期第一次阶段检测数学试题黑龙江省七台河市勃利县高级中学2021-2022学年高二上学期期末考试数学试题山东师范大学附属中学2022-2023学年高二上学期期中学业水平测试数学试题(已下线)模块三 专题2小题进阶提升练 (4)(苏教版)(已下线)第一章 空间向量与立体几何(基础、典型、新文化、压轴)分类专项训练-2022-2023学年高二数学考试满分全攻略(人教A版2019选择性必修第一册)
解题方法
6 . 已知,如图四棱锥
中,底面
为菱形,
,
,
平面
,E,M分别是BC,PD中点,点F在棱PC上移动.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/29/8ceebc56-c670-4bc1-b363-b723c1d78c84.png?resizew=204)
(1)证明无论点F在PC上如何移动,都有平面
平面
;
(2)当直线AF与平面PCD所成的角最大时,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/96127e45e2dd2494fccb1c0905951f0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/29/8ceebc56-c670-4bc1-b363-b723c1d78c84.png?resizew=204)
(1)证明无论点F在PC上如何移动,都有平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6501f1c913a4ef64957a2f01ab5baa15.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)当直线AF与平面PCD所成的角最大时,求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce747dfba7cd1b8054a3fc741629f257.png)
您最近一年使用:0次
2020-05-28更新
|
504次组卷
|
2卷引用:广西玉林市田家炳中学2020-2021学年高二上学期质量检测数学试题
7 . 如图1,
,点
为线段
的中点,点
为线段
上靠近
的三等分点.现沿
进行翻折,得到四棱锥
,如图2,且
.在图2中:
![](https://img.xkw.com/dksih/QBM/2020/5/26/2471209337217024/2471687538270208/STEM/9439b224-2678-4d92-84ff-0dbff6155f5f.png?resizew=168)
![](https://img.xkw.com/dksih/QBM/2020/5/26/2471209337217024/2471687538270208/STEM/ca106500-c163-479c-88a0-17166d2aab1d.png?resizew=153)
(1)求证:
平面
;
(2)求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cb2add1954da7c5365e4ef6a9e8bfa7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d3071be47c0be1fb8b89afe89fe1816.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f70d6f5baadf8139ee650b84f2fde70.png)
![](https://img.xkw.com/dksih/QBM/2020/5/26/2471209337217024/2471687538270208/STEM/9439b224-2678-4d92-84ff-0dbff6155f5f.png?resizew=168)
![](https://img.xkw.com/dksih/QBM/2020/5/26/2471209337217024/2471687538270208/STEM/ca106500-c163-479c-88a0-17166d2aab1d.png?resizew=153)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d0edb1508fc95765f3bb316bcb5252d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7af6b531f532eb39c26d36e9dd97254d.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59ac7cf883a6e586d06e3f33875bd95b.png)
您最近一年使用:0次
8 . 如图,菱形
中,
,
为
中点,将
沿
折起使得平面
平面
,
与
相交于点
,
是棱
上的一点且满足
.
![](https://img.xkw.com/dksih/QBM/2020/5/18/2465267479109632/2465526530899968/STEM/565544772d9b419e8ae0fb44c330324d.png?resizew=408)
(1)求证:
平面
;
(2)求二面角
的余弦值.
![](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/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d28c625d7ac6878957facc8274d459c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01ff27eea7545bb06f9472f91290c54e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.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/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8210bde150614e503abe6cf5945d2e34.png)
![](https://img.xkw.com/dksih/QBM/2020/5/18/2465267479109632/2465526530899968/STEM/565544772d9b419e8ae0fb44c330324d.png?resizew=408)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cdc4326d832adea0655b05083e6af7f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca67a5b8f69507c8b80379e86f90a8ce.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ec2524be492bca0d1566bf848066f10.png)
您最近一年使用:0次
2020-05-18更新
|
593次组卷
|
2卷引用:广西柳州市2019-2020学年高三4月模拟考试数学(理)试题
9 . 已知矩形
中,
,E,F分别为
,
的中点.沿
将矩形
折起,使
,如图所示.设P、Q分别为线段
,
的中点,连接
.
![](https://img.xkw.com/dksih/QBM/2020/4/10/2438548162363392/2439171394994176/STEM/bf029489ade44323960f9163f30df558.png?resizew=253)
(1)求证:
平面
;
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0041488020a3e19377b18a70fbf82e7c.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/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/946c16d99496d31ce4d87301a4793393.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4951b4ff78df3194a18e8daeb09e6171.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/7a5f1641947153c80b987320885a2b57.png)
![](https://img.xkw.com/dksih/QBM/2020/4/10/2438548162363392/2439171394994176/STEM/bf029489ade44323960f9163f30df558.png?resizew=253)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9abe6e8d1f4f1e8bdc46ddbae0cd789.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ab8a10e675354fa0c6e7da3d06b999d.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/445b51117626fbd3373e32acc514c64b.png)
您最近一年使用:0次
10 . 如图,在直三棱柱
中,平面
侧面
,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/29/5c4a6d9a-5411-4fcd-ba19-cde991e5d162.png?resizew=136)
(1)求证:
;
(2)若
,求锐二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21dee56b9f36ba8f76fe67b76383636b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4339a40ae9d1947ec3a4b3e2fa3a16cd.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/29/5c4a6d9a-5411-4fcd-ba19-cde991e5d162.png?resizew=136)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef0402dd5ae3db10281f9f1e11738bcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0218542daefa15910d5111b27e71f5b3.png)
您最近一年使用:0次