名校
1 . 如图,四边形ABCD为梯形,
,
,
,点
在线段
上,且
.现将
沿
翻折到
的位置,使得
.
![](https://img.xkw.com/dksih/QBM/2022/3/2/2927482149060608/2936643822362624/STEM/f93ceca9-e75b-4c76-b3e0-ff9295997956.png?resizew=251)
(1)证明:
;
(2)点
是线段
上的一点(不包含端点),是否存在点
,使得二面角
的余弦值为
?若存在,则求出
;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10df84d553a8826a7ce9bff4bf0d95b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/998329f9cdb86f5d60d7d5d70fc3781e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/86752e4373797b2231f76b074cbf75d0.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/9b937442ad4cc480adc11bb143559454.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/dbe40405cd7bd60d69dd535d6da85c00.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fbb42439079fa563100decbad833e10.png)
![](https://img.xkw.com/dksih/QBM/2022/3/2/2927482149060608/2936643822362624/STEM/f93ceca9-e75b-4c76-b3e0-ff9295997956.png?resizew=251)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbfbaf73297240eb116f22489519895a.png)
(2)点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc5adb5eb60ae4435a12d93854066298.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98553247801c03de24cf7e687016e655.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1174142f3bba761585b6bc2653009b36.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad0d6d600e2676abc87e05cde8aebc1a.png)
您最近一年使用:0次
2022-03-15更新
|
3289次组卷
|
9卷引用:重庆市荣昌中学校2022-2023学年高二上学期第一次月考数学试题
名校
2 . 已知
中角
,
,
所对的边为
,
,
,
,
,点
在
上,
,记
的面积为
,
的面积为
,
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16ca90e8a784f990c4097eec9219908d.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6834ac70927ae08d7d36a1922403c9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d70dc2c20619a4fc12a0cfda59af5b69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/037c8e495f4717fc194f2a10c9ca20ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab2a2834d80ff574e79eae8ca8d4e94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e097c8d4c948de063796bd19f85b3a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e0bd63f55069a3bc870915010b39225.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ccb62fc0eca198e45cb716282382121.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16ca90e8a784f990c4097eec9219908d.png)
您最近一年使用:0次
2021-05-31更新
|
1975次组卷
|
7卷引用:重庆市荣昌中学校2022-2023学年高二上学期第一次月考数学试题
重庆市荣昌中学校2022-2023学年高二上学期第一次月考数学试题江西省抚州市临川第一中学2021届高三5月模拟考试数学(文)试题(已下线)“超级全能生”2021届高三全国卷地区4月联考试题(甲卷)数学(理)试题(已下线)“超级全能生”2021届高三全国卷地区4月联考试题(乙卷)数学(理)试题陕西省2021届高三下学期教学质量检测(四)理科数学试题(已下线)专题05 解三角形-备战2022年高考数学(文)母题题源解密(全国乙卷)(已下线)专题6.15 平面向量及其应用全章综合测试卷(提高篇)-2022-2023学年高一数学举一反三系列(人教A版2019必修第二册)
3 . 已知四棱柱
的底面为菱形,
,
,
,
平面
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/20/324a68eb-6832-4cc9-83ab-c08c392ff6ea.png?resizew=204)
(1)证明:
平面
;
(2)求钝二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92105835f8075cb75dff244e908370b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bb8fb552b9e21dbaba74d11aa747790.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a23f01af749100e1888bba06268843db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ce03b310edce42191f9fa75a1c909ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7935fe3125f247b7bea4f065ce9ad985.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fd6edf5b50fea3628f602f397ceafcd.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/20/324a68eb-6832-4cc9-83ab-c08c392ff6ea.png?resizew=204)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/547a4b438e2e6687c7cd55ea08bbaae2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7935fe3125f247b7bea4f065ce9ad985.png)
(2)求钝二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/104bf24922707215be95a860cd533940.png)
您最近一年使用:0次
2019-12-27更新
|
1450次组卷
|
9卷引用:重庆市荣昌中学2023-2024学年高二上学期第一次月考数学试题
重庆市荣昌中学2023-2024学年高二上学期第一次月考数学试题山东省九校2019-2020学年高三上学期12月检测数学试题(已下线)卷07-备战2020年新高考数学自学检测黄金10卷-《2020年新高考政策解读与配套资源》(已下线)专题15 运用空间向量研究立体几何问题-2021年高考数学二轮优化提升专题训练(新高考地区专用)【学科网名师堂】浙江省2021届高三高考数学预测卷(一)新疆乌鲁木齐市第八中学2020-2021学年高二下学期第一阶段考试数学(理)试题(已下线)专题23 盘点空间面面角的问题——备战2022年高考数学二轮复习常考点专题突破福建省泉州第一中学2021-2022学年高二上学期期中考试数学试题山东省东营市第一中学2022-2023学年高三上学期期末数学试题