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)
更新时间:2022-11-11 17:39:29
|
相似题推荐
解答题-问答题
|
适中
(0.65)
名校
解题方法
【推荐1】如图,四棱柱
的侧棱
⊥底面ABCD,四边形ABCD为菱形,E,F分别为
,
的中点.
(1)证明:
四点共面;
(2)若
,求点A到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/23/433a813c-df7d-4865-9621-2330ada6a962.png?resizew=171)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b5cbd49398ea07b78a29bad53ce473d.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15a13c87c4a9b207b179170fce52bec4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6069dc466eec75bbeb3d5c9b51cb3a70.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐3】如图,四面体
中,
是
的中点,
和
均为等边三角形,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/14eddfb4-713f-4d0d-a660-992646dde256.png?resizew=196)
(Ⅰ)求证:
平面
;
(Ⅱ)求二面角
的正弦值.
![](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/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab2a2834d80ff574e79eae8ca8d4e94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/661ff55b5ebbadfb600989af3cfce2fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10c013bbe1fb6e9acf461548b5cf6cd2.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/14eddfb4-713f-4d0d-a660-992646dde256.png?resizew=196)
(Ⅰ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ce03b310edce42191f9fa75a1c909ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca67a5b8f69507c8b80379e86f90a8ce.png)
(Ⅱ)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ec2524be492bca0d1566bf848066f10.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1】如图,在三棱台ABC−A1B1C1中,△ABC为等边三角形,AA1⊥平面ABC,将梯形AA1C1C绕AA1旋转至AA1D1D位置,二面角D1−AA1−C1的大小为30°.
![](https://img.xkw.com/dksih/QBM/2022/4/1/2948553529303040/2953968848871424/STEM/86c7c9f930aa4dedbfac768e1a3e54e9.png?resizew=234)
(1)证明:A1,B1,C1,D1四点共面,且A1D1⊥平面ABB1A1;
(2)若AA1=A1C1=2AB=4,设G为DD1的中点,求直线BB1与平面AB1G所成角的正弦值.
![](https://img.xkw.com/dksih/QBM/2022/4/1/2948553529303040/2953968848871424/STEM/86c7c9f930aa4dedbfac768e1a3e54e9.png?resizew=234)
(1)证明:A1,B1,C1,D1四点共面,且A1D1⊥平面ABB1A1;
(2)若AA1=A1C1=2AB=4,设G为DD1的中点,求直线BB1与平面AB1G所成角的正弦值.
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
解题方法
【推荐2】如图,在长方体
中,
,
,点
在棱
上,且
.
![](https://img.xkw.com/dksih/QBM/2020/3/16/2421030274334720/2422238264344576/STEM/49013d22932c4d3c8bf1bc78f3e44382.png?resizew=126)
(1)求直线
与平面
所成角的正弦值;
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27db558e8db4c957654c8e5cecd2d2dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a50943279ee6f0299b3725eecd77bafd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f61bef8cea2d737bce9eb07ca6c2d8f.png)
![](https://img.xkw.com/dksih/QBM/2020/3/16/2421030274334720/2422238264344576/STEM/49013d22932c4d3c8bf1bc78f3e44382.png?resizew=126)
(1)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c74f12fea4418ec2ca3d1cc774c17747.png)
您最近一年使用:0次