解题方法
1 . 用光线照射物体,在某个平面上得到的影子叫做物体的投影,照射光线叫做投影线,投影所在的平面叫做投影面.由平行光线形成的投影叫做平行投影,由点光源发出的光线形成的投影叫做中心投影.投影线垂直于投影面产生的平行投影叫做正投影,投影线不垂直于投影而产生的平行投影叫做斜投影.物体投影的形状、大小与它相对于投影面的位置和角度有关.如图所示,已知平行四边形
在平面
内的平行投影是四边形
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/15/71cf6fa5-9cb4-4d8d-a907-fa7ccdcd6d3d.png?resizew=314)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/15/9fc4f21f-3f78-4976-887c-0642c3365737.png?resizew=314)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/15/462c058d-eb41-4d4a-ac0e-89fb806fef7a.png?resizew=314)
(1)若平行四边形
平行于投影面(如图
),求证:四边形
是平行四边形;
(2)在图
中作出平面
与平面
的交线(保留作图痕迹,不需要写出过程);
(3)如图
,已知四边形
和平行四边形
的面积分别为
,平面
与平面
的交线是直线
,且这个平行投影是正投影.设二面角
的平面角为
(
为锐角),猜想并写出角
的余弦值(用
表示),再给出证明.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d609847e2ff3d64e5a514582c3ead0e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/15/71cf6fa5-9cb4-4d8d-a907-fa7ccdcd6d3d.png?resizew=314)
图
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/15/9fc4f21f-3f78-4976-887c-0642c3365737.png?resizew=314)
图
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/15/462c058d-eb41-4d4a-ac0e-89fb806fef7a.png?resizew=314)
图
(1)若平行四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d609847e2ff3d64e5a514582c3ead0e.png)
(2)在图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
(3)如图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d609847e2ff3d64e5a514582c3ead0e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3637753af5ce86be9c23a9beb6b5067.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7021666155884a8aa345ed8eec3d2a01.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3637753af5ce86be9c23a9beb6b5067.png)
您最近一年使用:0次
名校
解题方法
2 . 如图,在多面体
中,平面
与平面
均为矩形且相互平行,
,设
.
平面
;
(2)若多面体
的体积为
:
(i)求
;
(ii)求平面
与平面
夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d17d4a6cf11cda87b3dfafaecdec683f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dff64de03b0302dbc12f2fc207b70d1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/336e0a8f5fbc1c44a02adab5a1fffb60.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dc99203b785fbdbd399bb03c7556fbf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
(2)若多面体
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d17d4a6cf11cda87b3dfafaecdec683f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a391005600bdd69c96750589f9adb048.png)
(i)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
(ii)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b03428a8f91a5674cb8f54766c165f7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ffee8b7eff437080a0936d837ceabe95.png)
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7日内更新
|
327次组卷
|
2卷引用:河南省信阳市新县高级中学2024届高三考前第二次适应性考试数学试题
解题方法
3 . 柯西不等式在数学的众多分支中有精彩应用,柯西不等式的n元形式为:设
,
,
不全为0,
不全为0,则
,当且仅当存在一个数k,使得
时,等号成立.
(1)请你写出柯西不等式的二元形式;
(2)设P是棱长为
的正四面体ABCD内的任意一点,点P到四个面的距离分别为
,
,
,
,求
的最小值;
(3)已知无穷正数数列
满足:
①存在
,使得
;
②对任意正整数i、
,均有
.
求证:对任意
,
,恒有
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/50a272adba0f1120109824440f0e252c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba031aac09bdee5b36549bb6e68bdb5e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/50a272adba0f1120109824440f0e252c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1602c6064af12eed3fd1291f8272d93c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/944ab11422d7221e45aa4cc6d868828b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34039940c47c92f3660e9dc7c27e5961.png)
(1)请你写出柯西不等式的二元形式;
(2)设P是棱长为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf298f00799cbf34b4db26f5f63af92f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5edf900c810371fb21297c15f86d8743.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b31ac1def558351e2e3ed1235c570530.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/342d0252c1b2f7d2a84b5c985d19d547.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d31659f106fba3c9750661eb0e3c3eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8dde93376f5d29f8f7d501122759b0ab.png)
(3)已知无穷正数数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76aef4cdcb5af742ce28003b7b6c8c20.png)
①存在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c24ecf9e59082e563372b12981d03fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1b5cbf6a7e19a347e95de7f119094fb.png)
②对任意正整数i、
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8598147874a35becc05e7bf4d90ce096.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a33ac34aa03dc7f0a5faad6dc664ec6.png)
求证:对任意
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5818ede14d21f6df9ef9c2bfe09286c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c229aec38946b710076588b7710381c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d191d6de821fbb06a51b5a20112db6de.png)
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解题方法
4 . 如图(1),正三棱柱
,将其上底面ABC绕
的中心逆时针旋转
,
,分别连接
得到如图(2)的八面体
,依次连接该八面体侧棱
的中点分别为M,N,P,Q,R,S,
(ⅰ)求证:
共面;
(ⅱ)求多边形
的面积;
(2)求该八面体体积的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a3a008a5ce2f3e0d93bf1b31f1e941d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1b73c7e51c2fbe79faa78e5287d2ccc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ff5cc57686ee7429fee0907651083c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78a40d2cf43fce0c99dff3470d554eb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ff5cc57686ee7429fee0907651083c4.png)
(ⅰ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8ae231960760617a585b8478185d8ac.png)
(ⅱ)求多边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac3662c929bd88085eb96dd4797482de.png)
(2)求该八面体体积的最大值.
您最近一年使用:0次
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解题方法
5 . 如图,在三棱锥
中,
分别是侧棱
的中点,
,
平面
.
平面
;
(2)如果
,且三棱锥
的体积为
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df2c4f20594ab1443c0d8dcce42895f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19bb1063e139610045f3bca5ca0b2766.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d26d8a9d64ad3c8cba28840b41ed7837.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58cc6184b191e6da43911e701121517e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a99ef32b30524326ce26f117cd7f5a91.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99b16cff607cdc2d69afc70dc778acbb.png)
(2)如果
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/547948c718075998e5995cfc6dcc4f92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c2ac20af67f3e0891be3102d70557ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d599cb4a589f90b0205f24c2e1fa021e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ffef235354f88fe062d31813e1fe56f.png)
您最近一年使用:0次
2024-05-28更新
|
1206次组卷
|
3卷引用:河南省信阳市新县高级中学2024届高三4月适应性考试数学试题
6 . 如图,在四棱台
中,
平面
,底面
为平行四边形,
,且
分别为线段
的中点.
.
(2)证明:平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fd66687a8c0d2d00ba430b040e9f647.png)
平面
.
(3)若
,当
与平面
所成的角最大时,求四棱台
的体积
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5845ccc0d735dc14c92a8926d9b1def6.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/417104247ce266ae42c3a9860f387272.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8e658d7985a600629fdf01517fc55c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cac18faf9da6221b788020ac0ddf709b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3fab0d028634166a93c5d80add98dc27.png)
(2)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fd66687a8c0d2d00ba430b040e9f647.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/638537c0a30676c73fea76c80e0f8bd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74bca84ad86c648d3bb20c8909c8da3f.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/faec6f7381dbe8daf15b2969f379e3d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e26d9636ad77369535852c6e4493446a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74bca84ad86c648d3bb20c8909c8da3f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be54e84508decfcce6d2fcbe6c8c1a92.png)
您最近一年使用:0次
2024-06-08更新
|
475次组卷
|
3卷引用:河南省创新发展联盟2023-2024学年高一下学期第三次月考(5月)数学试题
7 . 如图,四面体
中,
.
(1)求证:平面
平面
;
(2)若
,
①若直线
与平面
所成角为30°,求
的值;
②若
平面
为垂足,直线
与平面
的交点为
.当三棱锥
体积最大时,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f6c03029467212c952b89696f45456d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/4/23/2f9a3c3f-41a9-40b4-a456-a8b33158146b.png?resizew=164)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06123e81c41198c76a3335757fac2c93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1e156c3e4ffa35ed0ac6526c8d8753d.png)
①若直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf4c26f3f4d96117f087400a0f32ece8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b17622ea6f6f5afd1ad817a557e5889d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d742e749b1140b21512408d555f14a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7e4fa04825ac7d071968056322d88be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf4c26f3f4d96117f087400a0f32ece8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8be743a99c9d9c2775ced96ccf86d178.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91f0b8e4d79f6276b0ab054d887183a8.png)
您最近一年使用:0次
2024-04-19更新
|
768次组卷
|
4卷引用:江苏省南京市五所高中学校合作联盟2023-2024学年高二下学期期中学情调研数学试卷
江苏省南京市五所高中学校合作联盟2023-2024学年高二下学期期中学情调研数学试卷(已下线)模块三 专题2 解答题分类练 专题3 空间向量线性运算(苏教版)江苏高二专题02立体几何与空间向量(第二部分)江苏省扬州市扬州中学2023-2024学年高二下学期5月月考数学试题
解题方法
8 . 如图,在四棱锥P-ABCD中,底面ABCD为菱形,
,
平面AMHN,点M,N,H分别在棱PB,PD,PC上,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/5/14/393fa0ef-4b52-465f-ab47-6b7d48b874e7.jpg?resizew=186)
(1)证明:
;
(2)若H为PC的中点,
,PA与平面PBD所成角为60°,四棱锥
被平面
截为两部分,记四棱锥
体积为
,另一部分体积为
,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f945a69cf7e8213e50622125cde652f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e3c0430146b7b8d40ebb721a4d0de19.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/828247a3338571cb0d4ba2a5bf88929c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/5/14/393fa0ef-4b52-465f-ab47-6b7d48b874e7.jpg?resizew=186)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32d0710321d97361e5782124bbf7f0c9.png)
(2)若H为PC的中点,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cb96e0331eebe80ed1ff610faf531fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edd68fe22ed9909165aedc98d1d8e3a9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73bb075576cc0f585bda44277ac1d098.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4764374bd2fb78e59cd0b283637baeb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63055a5d6916f99d07fede49120753f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f737b04ce09bc7e1ed86dc9b3c85203b.png)
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9 . 如图1,在矩形
中,
是线段
上的一动点,如图2,将
沿着
折起,使点
到达点
的位置,满足点
平面
.
时,点
是线段
的中点,求证:
平面
;
(2)如图2,若点
在平面
内的射影
落在线段
上.
①是否存在点
,使得
平面
,若存在,求
的长;若不存在,请说明理由;
②当三棱锥
的体积最大值时,求点
到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cabc100677495f02ad4ec5d66c4282a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a5e0a51c9e14fb246b0ba0b231c1e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e69d2b798744645af88a4fa411344a83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6c72495428bbbd12cad3271b0654ee2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f9e5a462c0ca3b9e2c603750a3b433b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/328b9348891165ad4e0600421bfea18c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a8ec2583c364c079a7b1bfb1e8fe0c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a03203dd5ac79dd8c6707e4340773359.png)
(2)如图2,若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f9e5a462c0ca3b9e2c603750a3b433b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
①是否存在点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2b4e753ef119608188c46a50ec597e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c52b9478a450d15ff31eb1212a39ee6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/892909e49156f7dcc0650fcd65243877.png)
②当三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/47b610df769cfee80f361cd8a0a8c4aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
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10 . 如图,已知四边形
是直角梯形,
,
平面
是
的中点,E是
的中点,
的面积为
,四棱锥
的体积为
.
平面
;
(2)若P是线段
上一动点,当二面角
的大小为
时,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34ddc0e6db5f4acd18f4765e05d44bc8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21ec59cea09acc43a8178af846693cdf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06b39b0cfa27b633312db83601cf0359.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6830ebecddbd9759be626289c408e4f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/adbd3e8cf8325999cde03adf845d3dd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e5ba482836565abad208665cf7b9972.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6093eebca8f3ff82ce9298feb197e955.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca5dd496ee0c1170ef6dcc48266ee444.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6895da13331cb525f5850d7b7a02a847.png)
(2)若P是线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b74a85c6a0b3e431dc184d58f957090a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c02b54dc6b3e1bb6544f47d4c8743fcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/297cc0f9553ef0c5b537c5581eee934c.png)
您最近一年使用:0次