名校
1 . 如图1,AB为⊙O的直径,点P是直径AB上任意一点,过点P作弦
,垂足为P,过点B的直线与线段AD的延长线交于点F,且∠F=∠ABC.
![](https://img.xkw.com/dksih/QBM/2022/8/3/3036407790297088/3042341699436544/STEM/1f38f551e5a54e12bfa08392d396732b.png?resizew=302)
(1)若CD=
,BP=4,求⊙O的半径;
(2)求证:直线BF是⊙O的切线;
(3)当点P与点O重合时,过点A作⊙O的切线交线段BC的延长线于点E,在其它条件不变的情况下,判断四边形AEBF是什么特殊的四边形?请在图2中补全图象并证明你的结论.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b757f0c42ae5c9a2d6a4b19e5877b27.png)
![](https://img.xkw.com/dksih/QBM/2022/8/3/3036407790297088/3042341699436544/STEM/1f38f551e5a54e12bfa08392d396732b.png?resizew=302)
(1)若CD=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38387ba1cadfd3dfc4dea4ca9f613cea.png)
(2)求证:直线BF是⊙O的切线;
(3)当点P与点O重合时,过点A作⊙O的切线交线段BC的延长线于点E,在其它条件不变的情况下,判断四边形AEBF是什么特殊的四边形?请在图2中补全图象并证明你的结论.
您最近一年使用:0次
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解题方法
2 . 已知矩形ABCD的长与宽的比值为k,
分别为CD的四等分点,现将
沿AF向上翻折,将BCE沿BE向上翻折,使得
,
与四边形ABEF所成角均为
,且![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf4663fd2fba5440084cd793b67f2f71.png)
时,证明:平面
平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9a814b70236a108be5d6e7ff271fe92.png)
(2)当
时,是否存在P为线段BC上一点,使FP与平面ABD所成角为
,如果存在请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f8e496f4e3c850f3515525fd93148fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f8e496f4e3c850f3515525fd93148fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c17fe30d57340c823f3aaa8734fc38d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf4663fd2fba5440084cd793b67f2f71.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f644e851757e3836fe4844659416046.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1af463c1192cc6472c70ca84d9bdeb0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9a814b70236a108be5d6e7ff271fe92.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/894706f45d576906aca6acaea15634ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c030b25575d683af91c06e6a3e4f463.png)
您最近一年使用:0次
名校
解题方法
3 . 已知
为有穷正整数数列,且
,集合
.若存在
,使得
,则称
为
可表数,称集合
为
可表集.
(1)若
,判定31,1024是否为
可表数,并说明理由;
(2)若
,证明:
;
(3)设
,若
,求
的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67905ad53186bb2908b603bc14005d10.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/702dcfe2523f774f6bc4f075f3d24fe6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80566aaf96db9c785cda10dc0935c1c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84076d0854ef7c1a99a937fd50b25843.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c6985405452b5d04bd0d3305544cc2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c93e3391890fc877c761121b68cb927.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54119668d2f6cbc9ce0cb92310037713.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c93e3391890fc877c761121b68cb927.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b83efe191fb8adaf89737c03ef34d1b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c93e3391890fc877c761121b68cb927.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2ebfe653088b1a534d0731947db43d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/562441c2767a65f3671afa93b190126b.png)
(3)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ffceb52b543819898a9a6fc96d7337e2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7eab142f716f69be57d3f4ca2197894.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
您最近一年使用:0次
2024-01-20更新
|
1481次组卷
|
7卷引用:广东省梅州市大埔县虎山中学2023-2024学年高二下学期开学质量检测数学试卷
名校
4 . 记数列
的前
项和为
,且满足![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93a61d0858faaeca077fafec2564e763.png)
(1)求数列
的通项公式;
(2)数列
满足
,证明对任意
,
;
(3)某铁道线上共有
列列车运行,且每次乘坐到任意一列列车的概率相等,设随机变量
为恰好乘坐一次全部列车所乘坐的次数,试估算
的值(结果保留整数).
参考数据:
,
,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93a61d0858faaeca077fafec2564e763.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
(2)数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e5fc0b571e6545e133d36af338733b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e145b6046bc80d0ffecc61ac67c87ca1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7910db0b309011f31a4e31436fb32ebc.png)
(3)某铁道线上共有
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91488a5bb578d001827a4fd7a66b0592.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9891565348a420f9278f63642fab7dce.png)
参考数据:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0591d9f78b4f4f78c5bd6baaa602ae0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/289ad328bffb5f497153dc0e59939257.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3507fab2af0d78ae1fbbfa7d38cb146e.png)
您最近一年使用:0次
2023-08-15更新
|
1150次组卷
|
3卷引用:广东省华南师范大学附属中学2024届高三上学期开学测数学试题
5 . 已知数表
中的项
互不相同,且满足下列条件:
①
;
②
.
则称这样的数表
具有性质
.
(1)若数表
具有性质
,且
,写出所有满足条件的数表
,并求出
的值;
(2)对于具有性质
的数表
,当
取最大值时,求证:存在正整数
,使得
;
(3)对于具有性质
的数表
,当n为偶数时,求
的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aed47dfcc453bcc034a4c4490161da91.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd8f90d683ac488837f9f4f0d36cef32.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f3a3806d5350d02e410b1c008deeb77.png)
②
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53be326052e623a71b1e8bbdd9c6f31e.png)
则称这样的数表
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a29fef95ed54dcf5c653749f5e9d232.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
(1)若数表
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fce9d40adaecd9741d39abc0b3690431.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc0451ddb250fc0b16fb794652b6f93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fce9d40adaecd9741d39abc0b3690431.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/891f611bbc4558380467c4b4016092a9.png)
(2)对于具有性质
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a29fef95ed54dcf5c653749f5e9d232.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ae125a86cb3414cf27b3e5476e2dfb0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5df0e3592f57e9715f9ed56bfc98241f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d42cc575e90606d0fda516f1023c213.png)
(3)对于具有性质
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a29fef95ed54dcf5c653749f5e9d232.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ae125a86cb3414cf27b3e5476e2dfb0.png)
您最近一年使用:0次
2023-03-27更新
|
2838次组卷
|
11卷引用:广东省深圳市深圳科学高中2023-2024学年高二下学期开学考试数学试题
广东省深圳市深圳科学高中2023-2024学年高二下学期开学考试数学试题北京市东城区2023届高三一模数学试题专题12压轴题汇总(10、15、21题)专题07数列北京卷专题18数列(解答题)上海市上海中学2023-2024学年高二上学期期末考试数学试题(已下线)平行卷(提升)(已下线)数列新定义湖南省2024届高三数学新改革适应性训练二(九省联考题型)(已下线)黄金卷05(2024新题型)(已下线)2024年北京高考数学真题变式题16-21
名校
解题方法
6 . 如图,某景区绿化规划中,有一块等腰直角三角形空地
,
,
,
为
上一点,满足
.现欲在边界
,
(不包括端点)上分别选取
,
两点,并在四边形
区域内种植花卉,且
,设
.
(1)证明:
;
(2)
为何值时,花卉种植的面积占整个空地面积的一半?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/354c20e085fe1a99a8be03bd1d16b2f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1ef1f4982526c6e714fa8c50fbf7e0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1a3d7e3d361117f56c3f02c82687f43.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/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69a0982460d2fdf7f28aabe7f8ae01e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09d8f7b924d985f3c4af8cb913271ed7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c58605d04f34a2887781b049ca8f7c2.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/22/2ad8ac62-f98a-45df-a499-c17b02ba1dfe.png?resizew=152)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14091f3f56eb41a8be016478e932bed8.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43660b1543b3a2b46185f7629d28a963.png)
您最近一年使用:0次
2023-06-18更新
|
366次组卷
|
3卷引用:广东省深圳外国语学校2024届高三上学期第一次月考(入学考试)数学试题
名校
7 . 如图,圆柱的轴截面
为正方形,点
在底面圆周上,且
为
上的一点,且
为线段
上一动点(不与
重合)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/13/154f5638-5181-4e3f-93c1-33127df3bef6.png?resizew=154)
(1)若
,设平面
面
,求证:
;
(2)当平面
与平面
夹角为
,试确定
点的位置.
![](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/2675e2171c51891dc71f4284cda8a270.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41e435ea47d99bd1b504bf687eb0e2aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a051702dc3c9f71e25dec5abdd614426.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/13/154f5638-5181-4e3f-93c1-33127df3bef6.png?resizew=154)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31ac7b134d8d1136f90233addaa4723f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96f9d777e73144d82613eb2d1d8d7914.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d34b4e211e0adddf347e9db9c84e2985.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c7218869e4014b0f5bba8822e5f8a16.png)
(2)当平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/212a67f115d1cbe69f100b489babe5f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/678b28fddb166d90878d24d6e5481080.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac1a63ab608517bb10aa036783dfb51f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
您最近一年使用:0次
2022-10-11更新
|
1873次组卷
|
5卷引用:广东省汕头市潮阳实验学校2024届高三上学期摸底数学试题
广东省汕头市潮阳实验学校2024届高三上学期摸底数学试题广东省佛山市顺德区容山中学2022-2023学年高二上学期期中数学试题湖南省岳阳地区2023届高三上学期适应性考试数学试题福建省厦门第一中学2022-2023学年高二上学期期中考试数学试题(已下线)期中押题预测卷(考试范围:选择性必修第一册)(提升卷)-【单元测试】2022-2023学年高二数学分层训练AB卷(人教B版2019)
名校
8 . 给定正整数
,设集合
.对于集合
中的任意元素
和
,记
.设
,且集合
,对于
中任意元素
,若
则称
具有性质
.
(1)判断集合
是否具有性质
?说明理由;
(2)判断是否存在具有性质
的集合
,并加以证明;
(3)若集合
具有性质
,证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0704f453b2de48d36911f7db496bbf82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a839578f0b23c8aeba01730563a643e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9da8a33568ded09f3450bb153b0e5697.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/714ab9e5a6949c90c9bfdd118cfabeb7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d35e477c52dfbfb80f1fc315143c8b06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1368a045ba80f97383f3d9d7fcdc8f15.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cd94234d029d89c7b788b6d1e225db6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9855cb665c7f3785a17718be10538af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a2f08194bb663f1a086fa2f555ebf43.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/faa6d3ee76dcca88508ec0921f1adf0f.png)
(1)判断集合
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cbd6650ab1ac1f7426ec68c729671c41.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c581b105a7e14eae97d650ae73adf710.png)
(2)判断是否存在具有性质
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a742b9bb0812b7bb895851cc5a06fa1a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
(3)若集合
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/faa6d3ee76dcca88508ec0921f1adf0f.png)
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2023-03-27更新
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1988次组卷
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13卷引用:广东省深圳中学2023-2024学年高三寒假开学适用性考试数学试题
(已下线)广东省深圳中学2023-2024学年高三寒假开学适用性考试数学试题北京市西城区2023届高三一模数学试题专题12压轴题汇总(10、15、21题)专题01集合与常用逻辑北京市人大附中2022-2023学年高一下学期期中模拟数学试题(已下线)北京市丰台区2023届高三下学期3月一模数学试题变式题16-21北京卷专题02集合(解答题)(已下线)北京市第四中学2022~2023学年高一下学期期中数学试题北京市海淀区首都师范大学附属中学2024届高三上学期10月阶段检测数学试题(已下线)单元高难问题01集合中的新定义问题-【倍速学习法】(人教A版2019必修第一册)(已下线)专题03集合的运算-【倍速学习法】(人教A版2019必修第一册)北京市中关村中学2023-2024学年高二上学期期中练习数学试题(已下线)高三数学临考冲刺原创卷(二)
9 . 某数学课外活动小组在学习了勾股定理之后,针对图1中所示的“由直角三角形三边向外侧作多边形,它们的面积S1,S2,S3之间的关系问题”进行了以下探究:
(1)(类比探究)如图2,在Rt△ABC中,BC为斜边,分别以AB,AC,BC为斜边向外侧作Rt△ABD,Rt△ACE,Rt△BCF,若∠1=∠2=∠3,则面积S1,S2,S3之间的关系式为 ;
(2)(推广验证)如图3,在Rt△ABC中,BC为斜边,分别以AB,AC,BC为边向外侧作任意△ABD,△ACE,△BCF,满足∠1=∠2=∠3,∠D=∠E=∠F,则(1)中所得关系式是否仍然成立?若成立,请证明你的结论;若不成立,请说明理由;
(3)(拓展应用)如图4,在五边形ABCDE中,∠A=∠E=∠C=105°,∠ABC=90°,AB=2
,DE=2,点P在AE上,∠ABP=30°,PE=
,求五边形ABCDE的面积.
(1)(类比探究)如图2,在Rt△ABC中,BC为斜边,分别以AB,AC,BC为斜边向外侧作Rt△ABD,Rt△ACE,Rt△BCF,若∠1=∠2=∠3,则面积S1,S2,S3之间的关系式为 ;
(2)(推广验证)如图3,在Rt△ABC中,BC为斜边,分别以AB,AC,BC为边向外侧作任意△ABD,△ACE,△BCF,满足∠1=∠2=∠3,∠D=∠E=∠F,则(1)中所得关系式是否仍然成立?若成立,请证明你的结论;若不成立,请说明理由;
(3)(拓展应用)如图4,在五边形ABCDE中,∠A=∠E=∠C=105°,∠ABC=90°,AB=2
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10 . 如图(1),在△ABC中,AB=AC,D是AC的中点,延长BC至点E,使DE=DB,延长ED交AB于点F,探究
的值.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/24/94d99eef-fe38-4455-958c-a1c6ef26f001.png?resizew=424)
(1)先将问题特殊化.如图(2),当∠BAC=60°时,直接写出
的值;
(2)再探究一般情形.如图(1),证明(1)中的结论仍然成立;
(3)如图(3),在△ABC中,AB=AC,D是AC的中点,G是边BC上一点,
,延长BC至点E,点DE=DG,延长ED交AB于点F.直接写出
的值(用含n的式子表示).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b01700e039d8ef9005f21ce1b9ac8fc.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/24/94d99eef-fe38-4455-958c-a1c6ef26f001.png?resizew=424)
(1)先将问题特殊化.如图(2),当∠BAC=60°时,直接写出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b01700e039d8ef9005f21ce1b9ac8fc.png)
(2)再探究一般情形.如图(1),证明(1)中的结论仍然成立;
(3)如图(3),在△ABC中,AB=AC,D是AC的中点,G是边BC上一点,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4aece2c6595f8b38a3602ab3c5c0538a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b01700e039d8ef9005f21ce1b9ac8fc.png)
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