如图,是等腰直角三角形,
,
,
分别为
的中点,沿
将
折起,得到如图所示的四棱锥
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21f9157fce2a8339d281178c7c0bccbe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d99ecfa8dabb812e134aec7f611189a.png)
(2)当四棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48a1c8ccbabbbbb7bfcaa060807ac379.png)
(i) 写出最大体积;
(ii) 求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae72f1da4f5d540dc1e6f42ea08f952e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55bb03ab214cf6a07f4ecc48426d30da.png)
更新时间:2019-09-07 21:33:55
|
相似题推荐
解答题-问答题
|
适中
(0.65)
【推荐1】如图,在五面体
中,
平面
,
,
,
.
为线段
的中点,证明
平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
(2)若
,
,
,求平面
与平面
夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9142a8490de14a87eda628ffa7e28982.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca5dd496ee0c1170ef6dcc48266ee444.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38b5c1c5518b9332a2fb209c3621c700.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5d379ef9a50ae13b4264559ddd64da4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3570a95f68349fcd9417fcda62e78e7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db807b09cc550f476b3f8fa0c6a14425.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68b40d0d2f3cdd8981bb792ad87efb42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bb5b12692517a39c320f99a479eb055.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09d27bd71d79cb19eb554175e4ef0867.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2977ae4bfa32de8c6f0fb136205c4fe7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
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名校
解题方法
【推荐2】如图,四棱锥
,底面
为直角梯形,
,
面
,
,
,
为
中点.
![](https://img.xkw.com/dksih/QBM/2021/4/24/2706696080891904/2711449547907072/STEM/85fd4a8565344d25a37b27145807f902.png?resizew=160)
(1)证明:面
面
;
(2)点
是点
关于面
对称的点,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80c753cb1eb73fd8d136d00462970797.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f571396be1aa4a8914a66f7d7abd6381.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca5dd496ee0c1170ef6dcc48266ee444.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09afc70f448545336304333d5b5658b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61c756fc417050ceec023c837e63e67a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5575930a695a591ae96e3f7d9dbb608e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/2021/4/24/2706696080891904/2711449547907072/STEM/85fd4a8565344d25a37b27145807f902.png?resizew=160)
(1)证明:面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/395f045f08758964c556bd0791c0098d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c379709076119a61b85dd16fc1663d1.png)
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名校
【推荐3】如图1所示,四边形
中,
,
,
,
,
,点M为
的中点,点N为
上一点,且
,现将四边形
沿
翻折,使得
与
重合,得到如图2所示的几何体
,其中
.
(1)证明:
平面
;
(2)若点P是棱
上一动点,当二面角
的正弦值为
时,试确定点P的位置.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f571396be1aa4a8914a66f7d7abd6381.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc11331a7b2d2619b40ee6d34c3bd620.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07160f14b3b453bebb64cb2bf96dc85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7605ce6f221ce8cad191da0f84a216d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e53abbd672b82a02c4975f99fbbd2c37.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d57a6416245c80af20842ebde5aa32b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76c8ed20e806e8acda5b16f97345e5a8.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97f30533da2e1d2a958dc906c37eba9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c365c269aaa5a59a35884ad65507bdc1.png)
(2)若点P是棱
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/735056c174e8dd7906257a2a50a962a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0a3e7730e98d2af874d11664a5d084b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/827ccf0c04aa941ba20d5f4c6068b46b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/8/d5cfc656-f71c-4d1e-911a-9e138a5a75c2.png?resizew=343)
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解答题-问答题
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适中
(0.65)
【推荐1】在①PA⊥平面ABC,②BC⊥AC,③PB⊥BC三个条件中选两个条件补充在下面的线处,使得BC⊥平面PAC成立,请说明理由,并在此条件下进一步解答该题.
如图,在三棱锥P-ABC中,若_____,且PA=2AC=BC=2,求直线AB与平面PBC所成角的正弦值.
如图,在三棱锥P-ABC中,若_____,且PA=2AC=BC=2,求直线AB与平面PBC所成角的正弦值.
![](https://img.xkw.com/dksih/QBM/2020/10/20/2575062156451840/2578064701325312/STEM/6f0f0a75-d385-4d5a-b13d-77f4ae30b45b.png?resizew=170)
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解答题-证明题
|
适中
(0.65)
【推荐2】如图,四边形
与
均为菱形,设
与
相交于点
,若
,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/24/0aa6bb96-cec0-4033-b403-fe0743e039c8.png?resizew=159)
(1)求证:
平面
;
(2)求直线
与平面
所成角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f84f169e50dc59d4f7a8e1e36f5c847.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a8083bd859ca71ed9d103672eacff93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6b27bd5f1437c638082a7eec033b4c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/24/0aa6bb96-cec0-4033-b403-fe0743e039c8.png?resizew=159)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04268e9883c3a7f27357532220239cce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2194add18a7df1a23cf1554dc2da1b40.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a09d9d486b7f91ba933210dd013a7f2c.png)
您最近一年使用:0次