在四棱锥
中,底面ABCD是菱形,
底面ABCD,
,
,点M为PB的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/6/20/8cf38e64-c1a7-41ca-93eb-c9bc1e799f78.png?resizew=195)
(1)求证:
平面MAC;
(2)在棱CD上是否存在一点F,使得
,若存在,求PF与平面PAD所成角的正弦值;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3b10835116b9b777a666b438c907b49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9eee296a7d9fba487f1485c61580196f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/6/20/8cf38e64-c1a7-41ca-93eb-c9bc1e799f78.png?resizew=195)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36222db36e348661eb5f616820e4e60f.png)
(2)在棱CD上是否存在一点F,使得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf6de7703e18a31c8081be4d2d31bb01.png)
21-22高一下·吉林·阶段练习 查看更多[2]
更新时间:2022-06-20 15:10:11
|
相似题推荐
解答题-问答题
|
适中
(0.65)
解题方法
【推荐1】在直四棱柱
中,四边形
为菱形,
,
,E,F分别为棱
,
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/3/67427ec5-80df-4bb7-8591-fdbb9c25b912.png?resizew=214)
(1)证明:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
平面
;
(2)求平面
与平面
夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0af405392c66b86550a58f1cb9868717.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0ce06dbe9e1177468781ba4aff85ffc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/3/67427ec5-80df-4bb7-8591-fdbb9c25b912.png?resizew=214)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/638537c0a30676c73fea76c80e0f8bd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9afac7c616bbb14e1ed428a3c507c7dc.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ebb05874eb3353d754af24c9974273e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9afac7c616bbb14e1ed428a3c507c7dc.png)
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【推荐2】已知底面为菱形的四棱锥
中,
是边长为2的等边三角形,平面
平面ABCD,E,F分别是棱PC,AB上的点,从下面①②③中选取两个作为条件,证明另一个成立;①F是AB的中点;②E是PC的中点;③
平面PFD.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55a675310c8ba418e5a59beb7317e21e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93edc7bb513f40a89173121c8570cd65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7175df06e33cad4e6bbc3f2f6b0a2986.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/14/0a172466-2db4-4ed8-ba6c-612737f28337.png?resizew=178)
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】如图,在四棱锥
中,
平面
,
,
,
,
,
,E是
的中点.
平面
;
(2)若直线
与平面
所成的角和
与平面
所成的角相等,求四棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4adf90a8c2b29334cdc5aa5b554991f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f5de5aee06d877b0e0b20517a8fe3f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f8eeeea1c9652cacce976f8129cf520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecf7679c8b4b1e442ce4286d4b0e9c32.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97f30533da2e1d2a958dc906c37eba9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e6c2dad46a9052a4185a4f7b4ae8a2e.png)
(2)若直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e6c2dad46a9052a4185a4f7b4ae8a2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
解题方法
【推荐2】如图,在四棱锥
中,
,
分别为
的中点,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/da9b6ba4-071b-4572-a977-0deef266879f.png?resizew=135)
(1)求证:
平面
;
(2)求直线
与底面
所成角的大小
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8662205622d3b0c8dbfc543c64188f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c03e90ca7144c0ffbb6a6cc4a106784c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/382b1cf964713bd58885269081903dc1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a29f52897bd8e15c93884d843555bd7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cca433260b7cf14e30258592ce007fe2.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/da9b6ba4-071b-4572-a977-0deef266879f.png?resizew=135)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ebc26eda15abd72b7efe68af47639a5b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c66d99a6a8415ddad22bbed33b64cfb.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7e4fa04825ac7d071968056322d88be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ce735bef8c7fc6a1ddcebd449e38f7e.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3】某厂根据市场需求开发折叠式小凳(如图所示).凳面为三角形的尼龙布,凳脚为三根细钢管,考虑到钢管的受力和人的舒适度等因素,设计小凳应满足:①凳子高度为30cm,2三根细钢管相交处的节点
与凳面三角形
重心的连线垂直于凳面和地面.
![](https://img.xkw.com/dksih/QBM/2021/10/11/2827315184132096/2829814404890624/STEM/b401253acf5a47f2a599d0f72066a73f.png?resizew=221)
(1)若凳面是边长为20cm的正三角形,三只凳脚与地面所成的角均为45°,确定节点
分细钢管上下两段的比值(精确到0.01);
(2)若凳面是顶角为120°的等腰三角形,腰长为24cm,节点
分细钢管上下两段之比为2∶3,确定三根细钢管的长度(精确到0.1cm)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://img.xkw.com/dksih/QBM/2021/10/11/2827315184132096/2829814404890624/STEM/b401253acf5a47f2a599d0f72066a73f.png?resizew=221)
(1)若凳面是边长为20cm的正三角形,三只凳脚与地面所成的角均为45°,确定节点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
(2)若凳面是顶角为120°的等腰三角形,腰长为24cm,节点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
您最近一年使用:0次