如图,在四棱锥
中,底面
是菱形,侧面
是直角三角形,
,点
是
的中点,且平面
平面
.证明:
![](https://img.xkw.com/dksih/QBM/2016/5/31/1572660084457472/1572660090650624/STEM/c51055ed8d5a4d8ebef12c4c57a4b8f6.png)
(1)
平面
;
(2)平面
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6153163fecdf3f410411048428ccaef5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c7c28e1964509d008de51a26920f777.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6975ec118f40dc2feb16fb2dcde3285c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://img.xkw.com/dksih/QBM/2016/5/31/1572660084457472/1572660090650624/STEM/c51055ed8d5a4d8ebef12c4c57a4b8f6.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12d8677ae5ca7acf874d93789425d172.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/926584088b939200d88e64318f2d4e6c.png)
(2)平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/932fa5b69598e262129c5be86ed64376.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/926584088b939200d88e64318f2d4e6c.png)
更新时间:2016-12-04 08:08:03
|
相似题推荐
解答题-问答题
|
适中
(0.65)
名校
【推荐1】如图1,在平行四边形
中,
,将
沿
折起,使得点
到点
的位置,如图2,设经过直线
且与直线
平行的平面为
,平面
平面为
,平面
平面为
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/31/fcccad47-00ea-46d7-991d-7a91bd1013be.png?resizew=348)
(1)证明:
;
(2)若
,求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6686c197504aa6d73ad8475ff7748665.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac451db3443cabb204f96c31fd4a02e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/670684ed4962fcebce7b5a140510d066.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b523d2774d88853fd1709ac5fb9d443.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/670684ed4962fcebce7b5a140510d066.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e34bed0f3c81c0175e03bb3ceb03c0f0.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/31/fcccad47-00ea-46d7-991d-7a91bd1013be.png?resizew=348)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a93a52c2b943e4c70ace99ed802d2b5.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff0a0c299356c26338d4153748e8a61d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b33b7213d99a817bff19bcf740a0697c.png)
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解答题-证明题
|
适中
(0.64)
【推荐2】正
的边长为2,
是
边上的高,
分别是
和
的中点(如图(1)).现将
沿翻折成直二面角
(如图(2)).在图(2)中:
![](https://img.xkw.com/dksih/QBM/2016/5/10/1572629506252800/1572629511708672/STEM/38d5e306d13a477299f990dc0fee2ceb.png)
(1)求证:
平面
;
(2)在线段
上是否存在一点
,使
?证明你的结论;
(3)求二面角
的余弦值.
![](https://img.xkw.com/dksih/QBM/2016/5/10/1572629506252800/1572629511708672/STEM/0675c286c3cb438585ac2f9b67d0f800.png)
![](https://img.xkw.com/dksih/QBM/2016/5/10/1572629506252800/1572629511708672/STEM/07963e3dadb447d091501a49411fcf5e.png)
![](https://img.xkw.com/dksih/QBM/2016/5/10/1572629506252800/1572629511708672/STEM/7b499e7a04ba4d38b028550cb36e7705.png)
![](https://img.xkw.com/dksih/QBM/2016/5/10/1572629506252800/1572629511708672/STEM/0a245c041053483991cc472b42383a4d.png)
![](https://img.xkw.com/dksih/QBM/2016/5/10/1572629506252800/1572629511708672/STEM/18e4dd3ed4eb4c42aaff38c98423364a.png)
![](https://img.xkw.com/dksih/QBM/2016/5/10/1572629506252800/1572629511708672/STEM/dea62cbfc42c4007b7b7345555c57fb1.png)
![](https://img.xkw.com/dksih/QBM/2016/5/10/1572629506252800/1572629511708672/STEM/0675c286c3cb438585ac2f9b67d0f800.png)
![](https://img.xkw.com/dksih/QBM/2016/5/10/1572629506252800/1572629511708672/STEM/020534bd75fc4cce8b883c621cc13737.png)
![](https://img.xkw.com/dksih/QBM/2016/5/10/1572629506252800/1572629511708672/STEM/38d5e306d13a477299f990dc0fee2ceb.png)
(1)求证:
![](https://img.xkw.com/dksih/QBM/2016/5/10/1572629506252800/1572629511708672/STEM/2fdddf16856c44ba9406a7429bce8253.png)
![](https://img.xkw.com/dksih/QBM/2016/5/10/1572629506252800/1572629511708672/STEM/74b51661ce834a34bdaf2cd3ae564b9a.png)
(2)在线段
![](https://img.xkw.com/dksih/QBM/2016/5/10/1572629506252800/1572629511708672/STEM/dea62cbfc42c4007b7b7345555c57fb1.png)
![](https://img.xkw.com/dksih/QBM/2016/5/10/1572629506252800/1572629511708672/STEM/2f4bdc4497ad463db02811a5ab8a9006.png)
![](https://img.xkw.com/dksih/QBM/2016/5/10/1572629506252800/1572629511708672/STEM/9a9d1970ab34459ca176ba3f47098898.png)
(3)求二面角
![](https://img.xkw.com/dksih/QBM/2016/5/10/1572629506252800/1572629511708672/STEM/4ce62353534943dd80241cd138613f57.png)
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解答题-证明题
|
适中
(0.65)
【推荐1】如图,四棱锥P-ABCD的底面为正方形,平面
平面ABCD,
.
![](https://img.xkw.com/dksih/QBM/2020/10/15/2571751481794560/2573481519177728/STEM/37dcd70645524c6cb03551414d068bee.png?resizew=143)
(1)求证:
;
(2)若直线PA与BC所成角为
,求平面PAD与平面PBC所成锐二面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93edc7bb513f40a89173121c8570cd65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62974d34de3a12418d6b700420afd1b2.png)
![](https://img.xkw.com/dksih/QBM/2020/10/15/2571751481794560/2573481519177728/STEM/37dcd70645524c6cb03551414d068bee.png?resizew=143)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/545e18836bc7fee22f8f813a6f525d93.png)
(2)若直线PA与BC所成角为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af9955b5aebb73cd84447e8541f901ac.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐2】如图所示,在四棱锥PABCD中,PA⊥平面ABCD,AC⊥AD,AB⊥BC,∠BAC=45°,PA=AD=2,AC=1.
![](https://img.xkw.com/dksih/QBM/2016/1/8/1572425401917440/1572425407971328/STEM/c74046a7-0a53-4b02-ac77-d2b0bb26c8d5.png?resizew=195)
(1)证明:PC⊥AD;
(2)求二面角A-PC-D的正弦值.
![](https://img.xkw.com/dksih/QBM/2016/1/8/1572425401917440/1572425407971328/STEM/c74046a7-0a53-4b02-ac77-d2b0bb26c8d5.png?resizew=195)
(1)证明:PC⊥AD;
(2)求二面角A-PC-D的正弦值.
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