已知棱长为1的正方体
中.
平面
;
(2)求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f11af46fe44e3c454751ff57a8b10b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73845d4d663b3de0b281611fe2c762fe.png)
(2)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/010df4ca6f618ea64d3f91b2d9530822.png)
更新时间:2021-10-24 07:04:32
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相似题推荐
解答题-证明题
|
较易
(0.85)
名校
解题方法
【推荐1】在四棱锥
中,
平面
,
.四边形
为梯形,
.
![](https://img.xkw.com/dksih/QBM/2021/3/6/2672272155590656/2672349544833024/STEM/6c2638d6-3e26-419e-b57a-b9564f80f04b.png)
(1)求证:
平面
;
(2)求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4503cbce25b3c763c3677b042125efa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52a9f7422878a294a792fbb2e962b6cf.png)
![](https://img.xkw.com/dksih/QBM/2021/3/6/2672272155590656/2672349544833024/STEM/6c2638d6-3e26-419e-b57a-b9564f80f04b.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30067b7b236d17af8a462f96a58d11bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59ac7cf883a6e586d06e3f33875bd95b.png)
(2)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/25c0d515775fa08afc81ed7c281ee89a.png)
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解答题-问答题
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解题方法
【推荐2】如图,正方体
的棱长为
,将它沿相邻三个面的对角线截出一个三棱锥
,求剩下的几何体的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6c459662d5cc28d6b497b07f6456a96.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6dbe9cd323bb82d921cf64e512a2167.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/22/2b1836e9-8869-4a53-b00c-162edc27b767.png?resizew=166)
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解答题-证明题
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较易
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【推荐1】如图所示,直角梯形ACDE与等腰直角
所在平面互相垂直,F为BC的中点,
,AE∥CD,
.
(Ⅰ)求证:
∥平面
;
(Ⅱ)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f2333da32638ec636fa1e69e750ca4a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e71931753854b4e6fcf9103f78263fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a2293c8f02641303491b749cece9692b.png)
(Ⅰ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
(Ⅱ)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e06b49101b7d075b170d20daa2c98c5.png)
![](https://img.xkw.com/dksih/QBM/2012/2/22/1570764439601152/1570764444925952/STEM/cabe88faa1894a0899a214d78a97bdc8.png)
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【推荐2】如图,在四棱锥
中,四边形ABCD是矩形,M,N分别为BC,PD的中点.
![](https://img.xkw.com/dksih/QBM/2022/4/25/2965909270134784/2967976003092480/STEM/97179004-f4e7-43b9-b474-9a1a20606acd.png?resizew=162)
(1)证明:
平面
;
(2)若K为AD的中点,证明:平面
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://img.xkw.com/dksih/QBM/2022/4/25/2965909270134784/2967976003092480/STEM/97179004-f4e7-43b9-b474-9a1a20606acd.png?resizew=162)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7592c4f01c8e06c7ee90df5b9413a9f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
(2)若K为AD的中点,证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44b246f298023600b72c0548e9790b29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
您最近一年使用:0次