如图,设
是边长为
的正三角形,
平面
,
,若
,
是
的中点.
(1)证明:
平面
;
(2)求
与平面
所成角的正弦值. .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/689c065652544780be8b33ae92cbb6d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4533be56aaf023156f6f5657b2d146fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23d89df4ecdf087a869e014227a2a257.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a36f7e5128bcf12583792fe8a4a4d8fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09afc70f448545336304333d5b5658b.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62871bb0dff211fc3bd80f9066c25b29.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/30/1bf8d937-4a1f-4081-85cb-ac9a0721046a.png?resizew=159)
更新时间:2019-04-18 13:05:04
|
相似题推荐
解答题-问答题
|
适中
(0.65)
【推荐1】如图,在正方体
中,
是
的中点,
是
内部或边界上的点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/10/c7067edd-53c7-4610-aa6e-4a4f62c3471f.png?resizew=162)
(1)证明:
平面
;
(2)求直线
与平面
所成角的正弦值的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9a0c3a4e61b97fa9bc58f3179fc2958.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abf80148409afb32ced0b4f59f1ba709.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8385e82b5db466dbec438443a39934cf.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/10/c7067edd-53c7-4610-aa6e-4a4f62c3471f.png?resizew=162)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/932a04304f2d4975955d4baabb2deeea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29953579af8f8458bd3be0d75491da4f.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63a253c7fdf589ee3dece13d5b5b5732.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29953579af8f8458bd3be0d75491da4f.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐2】如图,在三棱台
中,
在面
内的射影恰好为
中点
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/29/d99c51b6-1c99-49d3-8c04-6bc9ba052d2f.png?resizew=135)
(1)求证:
平面
;
(2)若
,求二面角
的大小.
![](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/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9e446f5750ea01a0af48a6b3a670b87.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/29/d99c51b6-1c99-49d3-8c04-6bc9ba052d2f.png?resizew=135)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e56fdf217165748fafe938b64fa08179.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb88c278e18d776f165bc571031071d8.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4281235f451ef2935f884766e51b5b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5e5c679a0e221e02292b1c8b9e803fb.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
解题方法
【推荐1】在多面体
中,
,
,
,
,
,平面
平面
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/30/5b41a840-320f-4493-a57b-c970c43693ce.png?resizew=191)
(1)证明:
;
(2)求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9142a8490de14a87eda628ffa7e28982.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b430e98ea87209da6b3bbda34ea67c1a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f121eabff3c62c1a196d9ca5f6f83f0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f571396be1aa4a8914a66f7d7abd6381.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd7a42341edbc0b01ab0769c4c02c3e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/628501936b67eb3d91d355c32c84f5f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cf9a6db3571fa57bfa2d5e4d44c51b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09afc70f448545336304333d5b5658b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/30/5b41a840-320f-4493-a57b-c970c43693ce.png?resizew=191)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4999d4fbcbe15f78c29d518f25d317c2.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/422210c777ac0d625bbd81cc7601bf9b.png)
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】如图所示,四棱锥
中,四边形
是直角梯形,
底面
,
为
的中点,
点在
上,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/28/c8692aee-1cff-48e3-ac3b-b0ec3b798f4a.png?resizew=195)
(1)证明:
平面
;
(2)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/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/923ccdf79a1b5f4020b68b339a48d2a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a0b9f53b4b1ad97cbd9195163d0abf8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d19bfc3ea403f00432a246a0a49de0b8.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/28/c8692aee-1cff-48e3-ac3b-b0ec3b798f4a.png?resizew=195)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7592c4f01c8e06c7ee90df5b9413a9f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
您最近一年使用:0次