如图,AB是圆柱的底面直径且AB=2,PA是圆柱的母线且PA=2,点C是圆柱底面面圆周上的点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/21/8ceafff5-34be-4137-96e1-b5b3e779bc40.png?resizew=115)
(1)求证:BC⊥平面PAC;
(2)若AC=1,D是PB的中点,点E在线段PA上,求CE+ED的最小值.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/21/8ceafff5-34be-4137-96e1-b5b3e779bc40.png?resizew=115)
(1)求证:BC⊥平面PAC;
(2)若AC=1,D是PB的中点,点E在线段PA上,求CE+ED的最小值.
更新时间:2022-04-23 09:00:30
|
相似题推荐
【推荐1】在
中,角
,
,
的对边分别为
,
,
,
,
.
(1)若
还同时满足下列三个条件中的两个:①
,②
,③
,请指出这两个条件,并说明理由;
(2)若
,求
的周长.
![](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/01f641f5538b6b76cd5f02d006b66d57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/252a0abdf74fa33db277cab802a2746a.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f34365e5040ce6944115c8da61bf110.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65f9c88edac18a30697feb5a9956b70b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2be103fd3ce46a6b6f271e60523597c3.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a48d6a09f955918ec2dde5ebf8296c34.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
解题方法
【推荐2】已知
的面积为
,且内角
是
,
的等差中项.
(1)若
,求边
的长;
(2)当
边上中线
取最小值时,试判断
的形状.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/adbd3e8cf8325999cde03adf845d3dd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a53db0dbb7a77f8e6984258f0a614695.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐1】轴截面为正方形的圆柱叫做等边圆柱,已知某等边圆柱的轴截面面积为
,求该等边圆柱的底面周长和高.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e89daa260fa54127e2885b0162d1274.png)
您最近一年使用:0次
解答题-应用题
|
适中
(0.65)
名校
【推荐2】中国历史悠久,积累了许多房屋建筑的经验.房梁为柱体,或取整根树干而制为圆柱形状,或作适当裁减而制为长方体形状,例如下图所示.
(1)假设上表中的三种梁的截面面积相等,请问哪一种梁的截面形状最好?并具体说明;
(2)宋朝学者李诫在《营造法式》中提出了矩形截面的梁的截面长宽之比应定为
的观点.考虑梁取材于圆柱形的树木,设矩形截面的外接圆的直径为常数D,如下图所示,请问
为何值时,其抗弯截面系数取得最大值,并据此分析李诫的观点是否合理.
圆形截面 | 正方形截面 | 矩形截面 | |
条件 | r为圆半径 | a为正方形边长 | h为矩形的长,b为矩形的宽, |
抗弯截面系数 |
(1)假设上表中的三种梁的截面面积相等,请问哪一种梁的截面形状最好?并具体说明;
(2)宋朝学者李诫在《营造法式》中提出了矩形截面的梁的截面长宽之比应定为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b1dcdac71e394e495d069f64e1f1ce9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7812809ff90cd1b8b3015d745c6d4961.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐1】如图,在三棱锥
中,平面
平面
,
是以
为斜边的等腰直角三角形,
,O为
中点.
(1)求证:
平面
;
(2)求平面
与平面
夹角的余弦值;
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d077f6da8b2c00b152d4679aa2ed7f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9095a9bff4632df01886773c21c0b834.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/24/66db72ef-474e-4760-9aea-17b0834c2e36.png?resizew=160)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3e126c16032892966489053f44b9048.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
您最近一年使用:0次
解答题-作图题
|
适中
(0.65)
【推荐2】已知四棱锥
的底面
是平行四边形、侧棱
平面
,点
在棱
上, 且
, 点N是在棱
上的动点 (不为端点).
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/16/59285671-7446-4479-8c98-11e189f4d6e3.png?resizew=169)
(1)若N是棱
中点, 完成:
(i)画出
的重心G(在图中作出虚线),并指出点G与线段
的关系;
(ii) 求证:
平面
;
(2)若四边形
是正方形, 且
, 当点
在何处时, 直线
与平面
所成角的正弦值取得最大值, 并求出最大值.
![](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/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fd17a66a2af938c89e46f22e4d893b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc85ce5e111acf7162b8e1b5a3f6b220.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/16/59285671-7446-4479-8c98-11e189f4d6e3.png?resizew=169)
(1)若N是棱
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
(i)画出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acee03d4bb4667b6c345221b6c9b0fa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f50b3ae183997b707d16eb4e7f6712fa.png)
(ii) 求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa69a2247ad4d5231aa361349b12f97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1885efcff0b903e314057dd153578600.png)
(2)若四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2304c541406034dd83040e9a7887ed7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1885efcff0b903e314057dd153578600.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐3】如图所示,在四棱柱
中,侧棱
平面
,底面
是直角梯形,
,
,
.
![](https://img.xkw.com/dksih/QBM/2020/4/13/2440832867532800/2442064795213824/STEM/854280c0287b46e7b9f5e845364d1d89.png?resizew=207)
(1)证明:
平面
;
(2)若
,求二面角
的正弦值.
![](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/9060f03b9ee41d70d135b1e1a8902ce9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10df84d553a8826a7ce9bff4bf0d95b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8146229a98505930b9e59bea6a3651bf.png)
![](https://img.xkw.com/dksih/QBM/2020/4/13/2440832867532800/2442064795213824/STEM/854280c0287b46e7b9f5e845364d1d89.png?resizew=207)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4890e58791814622b87c4d60ea971f54.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/679748eab882a6be0fefd2cc300349a4.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8e2a44d05b1d387150c4b359e021ffc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e9f45c687c54e13c9c9503f50f6c202.png)
您最近一年使用:0次