已知四棱锥
如图所示,
,
,
,
,
为等边三角形.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/3/7229adb3-ad19-46a7-b7e7-923c9930424c.png?resizew=170)
(1)证明:
平面
;
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10df84d553a8826a7ce9bff4bf0d95b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bd6a2b112facda441f4e34bf5c145fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f121eabff3c62c1a196d9ca5f6f83f0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b0a361fc7a3779f73e39ae6783b639c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2205cffebf8c4d5f81d15ed7b85c8936.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/3/7229adb3-ad19-46a7-b7e7-923c9930424c.png?resizew=170)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3dad3fa0da7689f5580d4d80bd18c954.png)
更新时间:2021-08-20 23:10:08
|
相似题推荐
解答题-证明题
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适中
(0.65)
解题方法
【推荐1】如图,四棱锥E-ABCD中,EA=EB,AB//CD,AB⊥BC,AB=2CD.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/21/f1f8a40d-cd0b-4da2-bcfe-85b4367e418c.png?resizew=230)
(1)求证:AB⊥ED;
(2)线段EA上是否存在点F,使DF//平面BCE?若存在,求出
;若不存在,说明理由.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/21/f1f8a40d-cd0b-4da2-bcfe-85b4367e418c.png?resizew=230)
(1)求证:AB⊥ED;
(2)线段EA上是否存在点F,使DF//平面BCE?若存在,求出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c38757c4b09eddb4b0f3c472f4d90626.png)
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【推荐2】
为等腰直角三角形,
,
,
,
分别为
、
中点,将
沿
折起,使
到达
点,且
.
(1)证明:
;
(2)求二面角
的正切值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f121eabff3c62c1a196d9ca5f6f83f0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edc6b94f23607ff4261c371ec9425c8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.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/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea3e27f6e6d1592408508cc9fd14d480.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ea4d1a88e0b7065ed99ed24b921f434.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df6aaed07f0b69eee41de11613fc74de.png)
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【推荐1】在多面体
中,
,
,
平面
,
,
为
的中点.
(1)求证:
平面
;
(2)若
,求二面角
的平面角正弦值的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9142a8490de14a87eda628ffa7e28982.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb5a4bf8028cee9396367b68ea8e6f80.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e210c9698063925ad2df6b6c1749571.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f4c3f9dd5d0343597a7f58a1989b537.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2fa7bbd7831e9ff4f8cffc8889d34f05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/936c74c9a7edc81c037f4ea795d130bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/26/3db8ca47-7075-4025-a065-4e973e951940.png?resizew=134)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57f9d682e5d3cc8573574d8d11636758.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/474b9ae5b7ff355c6b74332d68eeb8e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8aad963ee7cdc7ff35a8dd23685589d1.png)
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解答题-证明题
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适中
(0.65)
真题
解题方法
【推荐2】如图,在底面为直角梯形的四棱锥
中,
平面ABCD,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/10/21f75acd-ab4d-4a42-832b-64481ca8d062.png?resizew=170)
(1)求证:
平面PAC;
(2)求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85b60d014f1283b6dad3d2b6d141b8ef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/491c3a4f72b84ebadd28b90711435adc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80e6971eccdf0b5f255b600eb6359ed5.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/10/21f75acd-ab4d-4a42-832b-64481ca8d062.png?resizew=170)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a5928c98b341b16d4b5a5b931d2929d.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a65bf87f74420270138ed73a2d38ca48.png)
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【推荐3】如图,在四棱锥
中,底面
是正方形,
为
的中点.
(1)证明:
平面
;
(2)已知
,
,求二面角
的余弦值.
![](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/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/20/e16ebf98-7027-436a-82d4-02a2ca4a05ff.png?resizew=162)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30067b7b236d17af8a462f96a58d11bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c66d99a6a8415ddad22bbed33b64cfb.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e93bba30163e31a3c61c98ebf53a0ab6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b44ac8c782bf34396ff8c8d2fe6022b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1f99a8e4053adc8bc59c19bca50ea69.png)
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解题方法
【推荐1】如图,在斜三棱柱
中,已知△ABC为正三角形,四边形
是菱形,D,E分别是AC,
的中点,平面
⊥平面ABC.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/16/982be6af-bc9f-4973-ab9b-d1b79dde097e.png?resizew=195)
(1)求证:
平面
;
(2)若
,在线段
上是否存在点M,使得
平面BDE?若存在,求
的值,若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d9a8181f7a7fe7f3fac872ce9534f15.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d9a8181f7a7fe7f3fac872ce9534f15.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/16/982be6af-bc9f-4973-ab9b-d1b79dde097e.png?resizew=195)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d26d8a9d64ad3c8cba28840b41ed7837.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aab6665a33c0a0c6f71803129b5bb72.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69a7bcc1efb8a2ff57d64b6d057da463.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f33fa5152ba27f7b8a28890cefca219.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb65f1c7dd635a4d78a724a3b9622c17.png)
您最近一年使用:0次
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解题方法
【推荐2】如图,在三棱柱中,平面
平面
,四边形
是矩形,四边形
是平行四边形,且
,
,
,以
为直径的圆经过点F.
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d62d30d732c3c6ee3f0dd66d7059356.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a09d9d486b7f91ba933210dd013a7f2c.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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