名校
1 . 如图,四边形
是一个边长为2的菱形,且
,现沿着
将
折到
的位置,使得平面
平面
,M,N是线段
上的两个动点(不含端点),且
,平面
与平面
相交于l.
![](https://img.xkw.com/dksih/QBM/2020/11/22/2598316578275328/2606199495032832/STEM/7ebfe5431ed6451b84c7db2830ef554f.png?resizew=227)
(l)求证:
;
(2)P为l一个动点,求平面
与平面
所成锐二面角的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fee63d7a67287c5254793609eef77f6b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a313fa9db2c50907e7341b07cdde8021.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/677d1863ff4d8ac1604b18149d4f320f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9a63295afb045510843bf4dd8d8fce0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8d8fbde036544d79a9099bdfcbebac0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1885efcff0b903e314057dd153578600.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
![](https://img.xkw.com/dksih/QBM/2020/11/22/2598316578275328/2606199495032832/STEM/7ebfe5431ed6451b84c7db2830ef554f.png?resizew=227)
(l)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03df2b57fa4838034d1a1fd2c6035158.png)
(2)P为l一个动点,求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0bf12905647aeeded72bbca21a63f319.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
您最近一年使用:0次
2020-12-03更新
|
1033次组卷
|
3卷引用:重庆市巴蜀中学2021届高三上学期适应性月考(四)数学试题
2 . 若直线
平行于平面
,则下面结论正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
A.直线![]() ![]() |
B.直线![]() ![]() |
C.直线![]() ![]() |
D.直线![]() ![]() |
您最近一年使用:0次
2022-04-25更新
|
720次组卷
|
3卷引用:天津市红桥区2016-2017学年高二上学期期中文科数学试题
天津市红桥区2016-2017学年高二上学期期中文科数学试题天津市红桥区2016-2017学年高二上学期期中理科数学试题(已下线)浙江省衢州、丽水、湖州三地市2022届高三(二模)数学试题变式题1-5
名校
3 . 在四棱锥
中,平面
平面
,底面
为直角梯形,
,
,
,
为线段
的中点,过
的平面与线段
,
分别交于点
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/18/6c56e855-6768-44df-9a67-e23fd104fa6b.png?resizew=172)
(1)求证:
平面
;
(2)若
,点
为
的中点,求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93edc7bb513f40a89173121c8570cd65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5acb763021bf166ca719d07223591d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4795ee1f96b430529934e2231b38885d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/639bec6242a4b3f7bfb4b7033a67328c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/18/6c56e855-6768-44df-9a67-e23fd104fa6b.png?resizew=172)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36148e5b0d89ba45bd98b91da00bf2b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1328e05d150f86dbe18656662eaa8f6b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5868de99a3e94b13316b0122f22d3f91.png)
您最近一年使用:0次
2020-12-01更新
|
956次组卷
|
4卷引用:福建省泉州市2020-2021学年高二上学期期中考试数学试题(B)
福建省泉州市2020-2021学年高二上学期期中考试数学试题(B)山东省菏泽市2020-2021学年高二(上)期中数学试题(b卷)(已下线)专题10 立体几何与空间向量-2021年高考冲刺之二轮专题精讲精析山西省平遥中学校2021-2022学年高二上学期期中数学试题
19-20高一·浙江杭州·期末
名校
4 . 已知四棱锥
的底面
是边长为4的正方形,
平面
,
,
为棱
上一点,且
,过
作平面
分别与线段
,
交于点
,
,且
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6dac92cdc67ef4ca31c4006d347ecf0d.png)
________ ,四边形
的面积为_________ .
![](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/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f566f6d9d8820c075a48eca82815de72.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d8b87af9fcfc0770593b24bd1204ddc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccaee8f228ff24e7c89879bb5b999cf2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.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/c193eaf4c5ea5a58ed82457cf92c6893.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6dac92cdc67ef4ca31c4006d347ecf0d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/391814bb9abb9c5178873d0f8c5d01fd.png)
您最近一年使用:0次
2020-11-30更新
|
524次组卷
|
3卷引用:【新东方】杭州新东方高中数学试卷386
19-20高一·浙江杭州·期末
解题方法
5 . 如图,已知斜三棱柱
中,点D,
分别为
上的点.若
平面
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/139eec4583cf67923b91b3df9e36e76a.png)
________ ;若平面
平面
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8228b61810f3d48ab3bb118d0e6a07c6.png)
_______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6795cae2df43a722e1355e9562d93c09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c152744e7eb9d9f86eaf937ed96a737.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cd597851c0db4e4de4769e10e09383b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fae7f4612c548b1f72a964ddb291cd2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/139eec4583cf67923b91b3df9e36e76a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bf345b86a78e5d8eba3bde4bae43774.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fae7f4612c548b1f72a964ddb291cd2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8228b61810f3d48ab3bb118d0e6a07c6.png)
![](https://img.xkw.com/dksih/QBM/2020/11/30/2604061256220672/2604155311636481/STEM/6ccbf24f3748408eab0f9e868ac4948b.png?resizew=176)
您最近一年使用:0次
2020高三·全国·专题练习
6 . 已知
为三条不同的直线,且
平面
,
平面
,
,则:①若
与
是异面直线,则
至少与
、
中的一条相交;②若
不垂直于
,则
与
一定不垂直;③ 若
,则必有
;④若
、
,则必有
.其中正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22b38aa358fe97b47a1d2cb32ffa1f91.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d29acfee233f0903449ca2da4960b05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39ba9eb6fc8e629ae7501020472f6a5b.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/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.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/72fbc714c63815dad9a27418f6492f16.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/347347d0147894ec926890e1eef45de0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/057cdb4057bca398a838e868efd360f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2293799d379200cf746e8450ebd5744f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5986f2991d45fbf3578f08f27d9fd7e.png)
A.①② | B.①④ |
C.②③ | D.①③ |
您最近一年使用:0次
7 . 如图,四面体ABCD中,点E,F分别为线段AC,AD的中点,平面
平面
,
,
,垂足为H.
![](https://img.xkw.com/dksih/QBM/2020/11/18/2595204682768384/2601979299405824/STEM/a02fff92-5ea3-4f41-8c97-80ec262792ac.png)
(1)求证:
;
(2)求证:平面
平面ABC.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7898ccc0ec40a1460fae5b5bf6bc001.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddb409de7d8056cdef2cd68080fe47ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7903326ef7b584fb53651194b7541fc0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41a7cf70f8772d8fea4599b18df2c88f.png)
![](https://img.xkw.com/dksih/QBM/2020/11/18/2595204682768384/2601979299405824/STEM/a02fff92-5ea3-4f41-8c97-80ec262792ac.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cf85bbbf81e16ba6da39bfebf0e09a7.png)
(2)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d443d65476dd21c8e1f9345b3f13439e.png)
您最近一年使用:0次
2020-11-27更新
|
2638次组卷
|
6卷引用:四川省蓉城名校联盟2020-2021学年高二第一学期期中联考理科数学试题
四川省蓉城名校联盟2020-2021学年高二第一学期期中联考理科数学试题四川省成都市蓉城名校联盟2020-2021学年高二(高中2019级)上学期期中联考文科数学试题(已下线)第二章+点、直线、平面之间的位置关系(能力提升)-2020-2021学年高一数学单元测试定心卷(人教版必修2)四川省内江市第六中学2020-2021学年高二上学期第三次月考数学理科试题四川省内江市第六中学2020-2021学年高二上学期第三次月考数学文科试题四川省成都市2020-2021学年高二上学期期中数学理科试题
2020高三·全国·专题练习
8 . 如图所示,在七面体
中,四边形
是边长为
的正方形,
平面
,
平面
,且
,
,
与
交于
点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/25/e70b79ec-64b1-4da4-8631-bf3be3be3525.png?resizew=148)
(1)在棱
上找一点
,使
平面
,并给出证明;
(2)求平面
与平面
所成角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c162736b719327a2acd7c4d313e1d93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb92a5e7dc942c44d0f6d7f3906ff804.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c611de332ba0c529d633a6cfe5240d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db65c1d07d95810704181b60bb25e3d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b5231649034fe4700f27f36c1a6147c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e5c62f22d7afc5627fcb86599faa8e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e0a8cfb3747c454e0698e12857ffae8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/25/e70b79ec-64b1-4da4-8631-bf3be3be3525.png?resizew=148)
(1)在棱
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd812d8cbe97b02449223ae94cc8511a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e8a20c1fc8a5620db5db3a74eb01201.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81166ad08996b441effff746335fdb87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/588690c4a218025937357ffab8d63c7a.png)
您最近一年使用:0次
2020高三·全国·专题练习
解题方法
9 . 如图1,点
、
分别是正
的边
、
的中点,点
是
的中点,将
沿
折起,使得平面
平面
,得到四棱锥
,如图2.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/17/9d8f48c2-5fd7-4858-945e-5d09d13d50f1.png?resizew=358)
(1)试在四棱锥
的棱
上确定一点
,使得
平面
;
(2)在(1)的条件下,求直线
与平面
所成角的正弦值.
![](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/0faed94a64b2dcfc6801b4fca0f16675.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/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc4b17ce6e90cd3810a3696262e94c1e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79c1acdd27cebb11e0266464b03b3afb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1d70676406f26d339465fe3473c0c05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b1e038b4e76b3a368731d3331522b8e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/17/9d8f48c2-5fd7-4858-945e-5d09d13d50f1.png?resizew=358)
(1)试在四棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b1e038b4e76b3a368731d3331522b8e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a78b6fb582468bdd5c3afa5461aefce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
(2)在(1)的条件下,求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
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2020-11-26更新
|
880次组卷
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5卷引用:专题47 空间向量与立体几何专题训练-2021年高考一轮数学(理)单元复习一遍过
(已下线)专题47 空间向量与立体几何专题训练-2021年高考一轮数学(理)单元复习一遍过(已下线)专题47 空间向量与立体几何专题训练-2021年高考一轮数学单元复习一遍过(新高考地区专用)(已下线)专题02+空间向量与立体几何大题专项练习-2020-2021学年【补习教材·寒假作业】高二数学(人教A版2019)(已下线)专题17+空间向量与立体几何大题专项练习-2020-2021学年【补习教材·寒假作业】高二数学(理)(人教A版)(已下线)专题17 空间向量与立体几何大题专项练习
2020高三·全国·专题练习
解题方法
10 . 如图,在四棱锥
中,底面
是平行四边形,
平面
,
,
,
是棱
上的一点.
![](https://img.xkw.com/dksih/QBM/2020/11/24/2600039995957248/2600577107099648/STEM/aec9418e4e914213be16de5976c7d6b8.png?resizew=156)
(1)证明:
平面
;
(2)若
平面
,求
的值.
![](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/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/251048aaeb0a16b152152a64d966b4f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c406e7d1e7977dd5b30ef81cfdc8e8d2.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/2020/11/24/2600039995957248/2600577107099648/STEM/aec9418e4e914213be16de5976c7d6b8.png?resizew=156)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2ffc6952e988d04f22f0fb2f7f0ab7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f571a1aac46c6d0cf440c0ec2846bf9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8c2b786c64e6a9ed2ec5670cde74f86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/add47889f6b4911133999a898d3666d3.png)
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