名校
1 . 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:黑龙江省哈尔滨市第六中学2018届高三上学期期中考试数学(理)试题
2 . 如图,四棱锥
中,底面
为平行四边形,
,
,
底面
.
(1)证明:
;
(2)设
,求点
到面
的距离.
![](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/c6e0b64d25ddd18454f88e40c45d7d8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c4e4a162f12d12a082b8d8fdd1aeab9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b07e317ffe7859e81b42ef4970e344a.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b610c9b9948d88eda8de0fb8d1cf972.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/21/26813d5c-7ffd-4886-9b5b-dc87dd6ea18e.png?resizew=158)
您最近一年使用:0次
2016-12-04更新
|
1190次组卷
|
9卷引用:【校级联考】黑龙江省牡丹江市第三高级中学2018-2019学年高二上学期期中考试数学试题
【校级联考】黑龙江省牡丹江市第三高级中学2018-2019学年高二上学期期中考试数学试题(已下线)2012届广西桂林中学高三11月月考文科数学试卷(已下线)2012—2013学年山西省太原五中高二10月月考国际班数学试卷2014-2015学年河北省满城中学高一下学期期中文科数学试卷2015-2016学年湖南省株洲十八中高一上学期期末数学试卷2017届湖南益阳市高三9月调研数学(文)试卷江苏省太仓市明德高级中学2017-2018学年高二上期中复习(立体几何)数学试题新疆克拉玛依市北师大克拉玛依附属中学2018-2019学年高一下学期期末考试数学试题江苏省南京师范大学附属实验学校2022-2023学年高一下学期5月月考数学试题
3 . 如图,四棱锥P-ABCD中,底面
为菱形,且
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/2/126456ab-d044-49db-8390-ab43465eef19.png?resizew=157)
(1)求证:
;
(2)若
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5448a23ab911e64fdb683091a2093ec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b86db010859f7a243badec02946a4e24.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/2/126456ab-d044-49db-8390-ab43465eef19.png?resizew=157)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9104a1941e557a85fd1496bc2b9be297.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff0a0c299356c26338d4153748e8a61d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e867e5c7ef4da37d8985ce82022060e.png)
您最近一年使用:0次
2016-12-03更新
|
798次组卷
|
8卷引用:黑龙江省大兴安岭地区呼玛县高级中学2022届高三上学期期末数学(理)试题
黑龙江省大兴安岭地区呼玛县高级中学2022届高三上学期期末数学(理)试题2016届河北省石家庄市高三复习教学质量检测一理科数学试卷2016届湖南省株洲市二中高三上学期期中理科数学试卷2015-2016学年河北省衡水二中高二上期中理科数学试卷【市级联考】甘肃省张掖市2018-2019学年高二上学期期末联考理科数学试题河北省实验中学2021届高三上学期期中数学试题河北省衡水市冀州区第一中学2020-2021学年高二下学期期中数学试题(已下线)高二数学下学期期中全真模拟卷(2)-2021-2022学年高二数学下学期考试满分全攻略(人教A版2019选修第二册+第三册)
4 . 如图
,在直角梯形
中,
,
∥
,
,
,将
沿
折起,使平面
平面
,得到几何体
,如图2所示.
![](https://img.xkw.com/dksih/QBM/2013/8/29/1571332669046784/1571332674142208/STEM/0235c08269d44ed7b84300259f2f6c01.png)
(Ⅰ)求证:
平面
;
(Ⅱ)求几何体
的体积.
![](https://img.xkw.com/dksih/QBM/2013/8/29/1571332669046784/1571332674142208/STEM/6d47d1cf0cfa444d885f7fde138d7138.png)
![](https://img.xkw.com/dksih/QBM/2013/8/29/1571332669046784/1571332674142208/STEM/2b78384800684cbe80fad518dae69627.png)
![](https://img.xkw.com/dksih/QBM/2013/8/29/1571332669046784/1571332674142208/STEM/ae03991cb0124b008780999004551b4b.png)
![](https://img.xkw.com/dksih/QBM/2013/8/29/1571332669046784/1571332674142208/STEM/d64dcb14b69047f6ab92883de3eae197.png)
![](https://img.xkw.com/dksih/QBM/2013/8/29/1571332669046784/1571332674142208/STEM/795f12f29cec4f04a2a702a19734cdd8.png)
![](https://img.xkw.com/dksih/QBM/2013/8/29/1571332669046784/1571332674142208/STEM/6801d822ed344a14a2f279cb2338e5a8.png)
![](https://img.xkw.com/dksih/QBM/2013/8/29/1571332669046784/1571332674142208/STEM/c60231db0bd84151879a013ce209d937.png)
![](https://img.xkw.com/dksih/QBM/2013/8/29/1571332669046784/1571332674142208/STEM/3b36e580f90c48adbd8fbe72130ff63f.png)
![](https://img.xkw.com/dksih/QBM/2013/8/29/1571332669046784/1571332674142208/STEM/41af9995198d438686e18a2333f51a20.png)
![](https://img.xkw.com/dksih/QBM/2013/8/29/1571332669046784/1571332674142208/STEM/b78ad559256f472c9541b21572c1d6af.png)
![](https://img.xkw.com/dksih/QBM/2013/8/29/1571332669046784/1571332674142208/STEM/9ff7170bfa994f5dac13ef85354c03d6.png)
![](https://img.xkw.com/dksih/QBM/2013/8/29/1571332669046784/1571332674142208/STEM/78f7830b36a84bdb98519517b07e30ab.png)
![](https://img.xkw.com/dksih/QBM/2013/8/29/1571332669046784/1571332674142208/STEM/0235c08269d44ed7b84300259f2f6c01.png)
(Ⅰ)求证:
![](https://img.xkw.com/dksih/QBM/2013/8/29/1571332669046784/1571332674142208/STEM/5fead1425e8f45d1804e13277b42722e.png)
![](https://img.xkw.com/dksih/QBM/2013/8/29/1571332669046784/1571332674142208/STEM/29a32fd2e7f243c08cb8c40ae93a46d6.png)
(Ⅱ)求几何体
![](https://img.xkw.com/dksih/QBM/2013/8/29/1571332669046784/1571332674142208/STEM/78f7830b36a84bdb98519517b07e30ab.png)
您最近一年使用:0次
2016-12-03更新
|
715次组卷
|
3卷引用:2014-2015学年黑龙江省龙东南四校高二下期末联考数学(文)试卷
10-11高一下·黑龙江鹤岗·期末
5 . 如图,在三棱锥
中,
,
为
中点.
(1)求证:
平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)在线段
上是否存在一点
,使二面角
的平面角的余弦值为
?若存在,确定
点位置;若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41e5db1d2fd912f77923e4c120a7dc19.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91fd684119cd366c5c024da2be7e7344.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d30637da200a07672ae231b4c5c09cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)在线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd9bd54c25b35857e6b602291f9b6062.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83303d3784492506fc44f2b4d6b07bc1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://img.xkw.com/dksih/QBM/2011/7/20/1570269026082816/1570269031669760/STEM/87f1cdc47fa342958ad2ad23f3db9b1b.png?resizew=238)
您最近一年使用:0次
6 . 在四棱锥
,
平面
,
,
,
,
.
(1)求证:平面
平面
;
(2)当点
到平面
的距离为
时,求二面角
的余弦值;
(3)当
为何值时,点
在平面
内的射影
恰好是
的重心.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d02bd5cfe804460846423e77f72db10f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb4564baf209de77802d46cda82995c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb3f9a5da641be35117fd35ba07a6aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99293d0e9aadc20e62a74acf864f042a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61a719cb3370fe6ddc7d2437dfaa9b8e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/513f52a3eb125158c4294aeff05fcb9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4aa9a88f1e317011b44e845003aeb281.png)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9557b784a82680a8c2d300060e9a2b85.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27d39f37441ee55dbc8f1a6ca199a66b.png)
(2)当点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7609a1407f1e965fc9f1235552dcf9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73b48694e35e9de0ece4ff9d5bfd6c6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8282f7fe4c82900a207e7267bf43b300.png)
(3)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae3142b1af4ce67d3e55417b4c0de257.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5233ab4347d3783c9416476c8aba9039.png)
![](https://img.xkw.com/dksih/QBM/2011/4/14/1570118536364032/1570118541893632/STEM/0cdb2aca26c64cbb89fec4a860b88e33.png?resizew=185)
您最近一年使用:0次
解题方法
7 . 如图,矩形ABCD中,
,
,
分别在线段BC和AD
上,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a9bfa68259d7a331be323b2038d628a.png)
,将矩形ABEF沿
折起.记折起后的矩形为MNEF,且平面MNEF
平面
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/14/31c3376c-1035-47da-9202-078caa4b073c.png?resizew=444)
(1)求证:
平面
;
(2)若
,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73ba94cec6c03980be9ca03774379fa2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
上,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a9bfa68259d7a331be323b2038d628a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1633988fd62a652de726ee92a917b52d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8bb0bd784f9ca4d5a099b5e55c9a0374.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/14/31c3376c-1035-47da-9202-078caa4b073c.png?resizew=444)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92f0e0d048793657294151529f0148fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13576338960eb920b0d69e91479d07dd.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38c5c9cc1ed4bce98b7fae77e70b227f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5bdeff879f62f66b12fbd4cb16e3b4a.png)
您最近一年使用:0次
名校
解题方法
8 . 如图,在三棱锥
中,
底面
,
,且
,点
是
的中点,
且交
于点
.
![](https://img.xkw.com/dksih/QBM/2019/5/7/2198533209505792/2198589188300800/STEM/2395c1f02c8a4b4cb7e0ac5553a15b6c.png?resizew=176)
(1)求证:
平面
;
(2)当
时,求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41e5db1d2fd912f77923e4c120a7dc19.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10c83f8945042b9c8fb2fbdac9308d62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45acdbac251ca6b76a166c1242e71df9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a93767331e9bac06a564973a9f4fc663.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d4db9b82b67efe45a02fca32bfcf5dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f04e6ed01c8f3778a64f055d33ee70c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c2bc5e50b8dfa02601c70822252854a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://img.xkw.com/dksih/QBM/2019/5/7/2198533209505792/2198589188300800/STEM/2395c1f02c8a4b4cb7e0ac5553a15b6c.png?resizew=176)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6deecf9ccb7b7879455050633219e09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1885efcff0b903e314057dd153578600.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/829018a6ca0aff95d89e3f7cd943274e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b97cf970548711b6bb15dc4a6dd68a6b.png)
您最近一年使用:0次
2016-12-04更新
|
915次组卷
|
4卷引用:【全国百强校】黑龙江省大庆实验中学2017-2018学年高一下学期期末考试数学(理)试题
9 . 如图,
是正方形,
是该正方体的中心,
是平面
外一点,
平面
,
是
的中点.
![](https://img.xkw.com/dksih/QBM/2016/5/30/1572653436821504/1572653443014656/STEM/206d713946cc4a089d2c4e251df0173d.png)
(1)求证:
平面
;
(2)求证:
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19807b67a48dedbd28fbb60dafd566d9.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/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://img.xkw.com/dksih/QBM/2016/5/30/1572653436821504/1572653443014656/STEM/206d713946cc4a089d2c4e251df0173d.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/373f735f0f04d11f1951eaef1bb78b6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f3f3cd7dc815e9baf79d40119a9498d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
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2016-12-04更新
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732次组卷
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10卷引用:黑龙江省牡丹江市第一高级中学2016-2017学年高一下学期期末考试数学试题
黑龙江省牡丹江市第一高级中学2016-2017学年高一下学期期末考试数学试题黑龙江省安达市田家炳高级中学2017-2018学年高一下学期期末考试数学试题2015-2016学年云南省西双版纳州景洪三中高一上学期期末数学试卷2015-2016学年西藏日喀则一中高一4月月考数学试卷2016-2017学年陕西省咸阳市高一上学期期末教学质量检测数学试卷福建省闽侯第四中学2017-2018学年高二上学期期中数学(理)试题新疆沙雅县第二中学2018-2019学年高二下学期期末数学试题青海省平安县第一高级中学2017-2018学年高二上学期期中考试数学(B卷)试题湖南省株洲市茶陵县第三中学2019-2020学年高一下学期入学考试数学试题云南省楚雄天人中学2019-2020学年高二4月学习效果监测数学(文)试题
10 . 如图,斜三棱柱
的底面是直角三角形,
,点
在底面内的射影恰好是
的中点,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/3/e64f0629-c26f-41c8-9469-a3af54644f1a.png?resizew=250)
(1)求证:平面
平面
;
(2)若二面角
的余弦值为
,求斜三棱柱
的侧棱
的长度.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a355958abf7dc0f2eb949584cb87907b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97c01fdc7bc471af0b264a04aef0823e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c04b0b1fd6979d5cf1d7be8f5109186a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/3/e64f0629-c26f-41c8-9469-a3af54644f1a.png?resizew=250)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61cdaadeae37736a1e6dd93fa1fe712f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9961e091f180e964a962adf6916f33c8.png)
(2)若二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6424823292a4b68e935d67d2a718424e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9237f95cb63d2e280e2ce8a4c5797255.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
您最近一年使用:0次