在正三棱锥
中,
、
分别为棱
、
的中点,且
.
![](https://img.xkw.com/dksih/QBM/2015/9/11/1572229475041280/1572229480955904/STEM/2ba52750b4c54f94a53a9e5ead3d1cd2.png)
(1)求证:直线
平面
;
(2)求证:平面
平面
.
![](https://img.xkw.com/dksih/QBM/2015/9/11/1572229475041280/1572229480955904/STEM/06a1a2bd819a44c982a525ad6cde88df.png)
![](https://img.xkw.com/dksih/QBM/2015/9/11/1572229475041280/1572229480955904/STEM/31e6e0f27e9e48be86cebe33864a9223.png)
![](https://img.xkw.com/dksih/QBM/2015/9/11/1572229475041280/1572229480955904/STEM/41469a49c14b4de586c547ff8df8bc98.png)
![](https://img.xkw.com/dksih/QBM/2015/9/11/1572229475041280/1572229480955904/STEM/940335b942964da888138fc6690f4f5a.png)
![](https://img.xkw.com/dksih/QBM/2015/9/11/1572229475041280/1572229480955904/STEM/960ff362f8da4645bd3dcf59ad26abee.png)
![](https://img.xkw.com/dksih/QBM/2015/9/11/1572229475041280/1572229480955904/STEM/b106e917b59340c384ebd38015c24826.png)
![](https://img.xkw.com/dksih/QBM/2015/9/11/1572229475041280/1572229480955904/STEM/2ba52750b4c54f94a53a9e5ead3d1cd2.png)
(1)求证:直线
![](https://img.xkw.com/dksih/QBM/2015/9/11/1572229475041280/1572229480955904/STEM/f38c6affd7034c46b6e7384380ce8c91.png)
![](https://img.xkw.com/dksih/QBM/2015/9/11/1572229475041280/1572229480955904/STEM/34c371fb18144b0ba07dda89b61665c3.png)
(2)求证:平面
![](https://img.xkw.com/dksih/QBM/2015/9/11/1572229475041280/1572229480955904/STEM/0721aeca5f464bd3ac7c553fde9eb777.png)
![](https://img.xkw.com/dksih/QBM/2015/9/11/1572229475041280/1572229480955904/STEM/f29f0ced562b4449b8ecd08a228540fe.png)
更新时间:2016-12-03 17:31:58
|
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解答题-问答题
|
适中
(0.64)
【推荐1】如图,直三棱柱
中,
分别是
的中点,
.
![](https://img.xkw.com/dksih/QBM/2016/6/30/1572850636652544/1572850642731008/STEM/8dd3ca3d70534e45865489d4df885201.png)
(1)证明:BC1∥平面A1CD
(2)求二面角D﹣A1C﹣E的正弦值.
![](https://img.xkw.com/dksih/QBM/2016/6/30/1572850636652544/1572850642731008/STEM/d2c175252b6241c7a0c882edc3fc1a0f.png)
![](https://img.xkw.com/dksih/QBM/2016/6/30/1572850636652544/1572850642731008/STEM/a2732c770191424c878bc464c17969ac.png)
![](https://img.xkw.com/dksih/QBM/2016/6/30/1572850636652544/1572850642731008/STEM/49477cb1398141e9af7e2c1b538fb39b.png)
![](https://img.xkw.com/dksih/QBM/2016/6/30/1572850636652544/1572850642731008/STEM/47f732b2e2e9434a878ce1544628636f.png)
![](https://img.xkw.com/dksih/QBM/2016/6/30/1572850636652544/1572850642731008/STEM/8dd3ca3d70534e45865489d4df885201.png)
(1)证明:BC1∥平面A1CD
(2)求二面角D﹣A1C﹣E的正弦值.
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2】如图,在五面体
中,四边形
是矩形,
,
,
,
,
为
的中点,
为线段
上一点,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/7/31ccc417-61cd-47b7-8b37-be7e5864807c.png?resizew=251)
(1)求证:
平面
;
(2)求证:
;
(3)求证:平面
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9165d9bfbb0f0d19eb482c2a4c1b29b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/613dedf2d90e58591b7ac4a250ac7b5d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/058f36d315245b63a811d5c6f348c17b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/735056c174e8dd7906257a2a50a962a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f94febfbf27f54ed0071cb59ac52719b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/7/31ccc417-61cd-47b7-8b37-be7e5864807c.png?resizew=251)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d46554105150391e671609fc6348a18.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bb10d645970e5860afd3430957fab6c.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a7a3dc3f3a02f4400e22dec2f2fee23.png)
(3)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09247d21654f0a9148dcf3232313e71c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1f1d7219cd40346442b33dba84deb5c.png)
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解答题-问答题
|
适中
(0.64)
【推荐1】如图,三棱柱
中,
,
,
.
![](https://img.xkw.com/dksih/QBM/2016/5/13/1572635652251648/1572635658575872/STEM/63a62e555c93430b8dc4f6c69596562d.png)
(Ⅰ)证明
;
(Ⅱ)若平面
⊥平面
,
,求直线
与平面
所成角的正弦值.
![](https://img.xkw.com/dksih/QBM/2016/5/13/1572635652251648/1572635658575872/STEM/4f3f4c5836c04357b29d0adc15b7ab81.png)
![](https://img.xkw.com/dksih/QBM/2016/5/13/1572635652251648/1572635658575872/STEM/0240e5126087490999433694a837e1a5.png)
![](https://img.xkw.com/dksih/QBM/2016/5/13/1572635652251648/1572635658575872/STEM/4bd2ac85a59f442a84b35be176da2658.png)
![](https://img.xkw.com/dksih/QBM/2016/5/13/1572635652251648/1572635658575872/STEM/48e426971b3b4af0a1310004b800a1b8.png)
![](https://img.xkw.com/dksih/QBM/2016/5/13/1572635652251648/1572635658575872/STEM/63a62e555c93430b8dc4f6c69596562d.png)
(Ⅰ)证明
![](https://img.xkw.com/dksih/QBM/2016/5/13/1572635652251648/1572635658575872/STEM/f19624d6f7324cadb68ecc2da646244f.png)
(Ⅱ)若平面
![](https://img.xkw.com/dksih/QBM/2016/5/13/1572635652251648/1572635658575872/STEM/baa6d5aefe934d23a145b280e0ecb414.png)
![](https://img.xkw.com/dksih/QBM/2016/5/13/1572635652251648/1572635658575872/STEM/71239ec572f4456fb08f311effadcce1.png)
![](https://img.xkw.com/dksih/QBM/2016/5/13/1572635652251648/1572635658575872/STEM/b61bdee89b834b919cc4ffa5c34e9fd7.png)
![](https://img.xkw.com/dksih/QBM/2016/5/13/1572635652251648/1572635658575872/STEM/17afa96382364ffd88166317b8d398eb.png)
![](https://img.xkw.com/dksih/QBM/2016/5/13/1572635652251648/1572635658575872/STEM/fa954aeaab5f46b1a518211925115bb4.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.64)
【推荐2】如图,平面ABEF⊥平面ABC,四边形ABEF为矩形,AB=BC.O为AB的中点,OF⊥EC.
![](https://img.xkw.com/dksih/QBM/2016/3/28/1572559096078336/1572559101714432/STEM/2d23fadf95ec4a75a58963b3b1ada846.png)
(1)求证:OF⊥FC ;
(2)若
时,求二面角F-CE-B的余弦值.
![](https://img.xkw.com/dksih/QBM/2016/3/28/1572559096078336/1572559101714432/STEM/2d23fadf95ec4a75a58963b3b1ada846.png)
(1)求证:OF⊥FC ;
(2)若
![](https://img.xkw.com/dksih/QBM/2016/3/28/1572559096078336/1572559101714432/STEM/753c74d400fd49a3b7aa5c8512ba0c8d.png)
您最近一年使用:0次