如图,三棱柱
的所有棱长都相等,点
在底面
上的射影恰好是等边
的中心.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/25/941187f0-8143-4ab5-961b-d8520740d1a6.png?resizew=205)
(1)证明:四边形
是正方形;
(2)设
分别为
的中点,求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18722354086c42e62334983fc50eb6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/25/941187f0-8143-4ab5-961b-d8520740d1a6.png?resizew=205)
(1)证明:四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91e1e4115d78e625e9e0f47cdade3286.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1857eadd6b23a87a1a5b4ffff584efd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/100da1c62b219145a42cabf619ccc0ce.png)
更新时间:2022-12-24 13:02:21
|
相似题推荐
解答题-问答题
|
适中
(0.65)
真题
【推荐1】如图,在
交AC于 点D,现将![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11dc70f0cbba35a2c43be6d24ab9ce4b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/25/4fd756bb-a11c-4aea-b47c-a56698a536be.png?resizew=247)
(1)当棱锥
的体积最大时,求PA的长;
(2)若点P为AB的中点,E为![](https://img.xkw.com/dksih/QBM/2011/6/16/1570240298082304/1570240303497216/STEM/91a0e1a42bd84f498f5dd90cbc38dcb4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb358045c0a768f7340c2ff65aae49f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11dc70f0cbba35a2c43be6d24ab9ce4b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/25/4fd756bb-a11c-4aea-b47c-a56698a536be.png?resizew=247)
(1)当棱锥
![](https://img.xkw.com/dksih/QBM/2011/6/16/1570240298082304/1570240303497216/STEM/2f06ed1eb5da49bfa646973b3a42d23f.png)
(2)若点P为AB的中点,E为
![](https://img.xkw.com/dksih/QBM/2011/6/16/1570240298082304/1570240303497216/STEM/91a0e1a42bd84f498f5dd90cbc38dcb4.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/25/63914963-a22f-460b-bf70-461327d0c6e0.png?resizew=247)
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,四棱锥
的底面是矩形,
底面
,
,M为
的中点,且
.
![](https://img.xkw.com/dksih/QBM/2022/3/23/2942537856557056/2946224414875648/STEM/8b9407bf-ee47-4c2f-8196-4d9c7e989b43.png?resizew=185)
(1)求
长;
(2)求平面
的法向量
与
夹角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.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/40d4d36ae30487030b827ce9413b9f13.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/186e5e7efe51fd25b9e38dc0fa23de9d.png)
![](https://img.xkw.com/dksih/QBM/2022/3/23/2942537856557056/2946224414875648/STEM/8b9407bf-ee47-4c2f-8196-4d9c7e989b43.png?resizew=185)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36f1a8e551cba7ec9f451749f60e628d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/888afd002858f23a84a8755a002bed7a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐1】如图,在多面体ABCDEF中,四边形ABCE和四边形CDEF是全等的直角梯形,且这两个梯形所在的平面相互垂直,其中
.
平面BCD;
(2)求平面BCD和平面ABF的夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da0b4ee0295c2c55e4a6c76d473b5ca3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8d2d217e9bcd059908f117dfc4d4259.png)
(2)求平面BCD和平面ABF的夹角的余弦值.
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,在棱长为3的正方体
中,E为棱
上一点,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/2/9d91585a-d7e0-4b94-888b-71b961755fc5.png?resizew=176)
(1)求点B到平面
的距离;
(2)求平面
与平面
夹角的余弦值.
![](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/0c35cd5ec4aab04a2cbc6bc72cb06481.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/2/9d91585a-d7e0-4b94-888b-71b961755fc5.png?resizew=176)
(1)求点B到平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e4755dc59cb5a03cd39879bc80fdbb9.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e4755dc59cb5a03cd39879bc80fdbb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1c1acd7da8817385417e1dff25bfe25.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】已知三棱柱
中,
,
,
平面
,
,
为
的中点,
为
上一点.请用空间向量知识解答下列问题:
(1)求证:
平面
;
(2)当
为
的中点时,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26cb239a35eb1f0563b5863d986859bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5845ccc0d735dc14c92a8926d9b1def6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b10134e7a46e6f6f7cb9d5e2371727d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/25/427635e6-17c0-420a-ac8a-8d864acf7e67.png?resizew=160)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44b190c8d3d7d7d0e6e959e8a52eae90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92e31d02b38f82bfa005385f1e17d364.png)
您最近一年使用:0次