解题方法
1 . 如图,在四棱柱
中,
⊥平面ABCD、底面ABCD为梯形.
∥
,
,
,Q为AD的中点,平面a经过直线
,
平面
直线l
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/19/4c23791e-935d-441d-8c36-30fbb73e2c84.png?resizew=180)
(1)请在图中画出直线l,写出画法并说明理由
(2)求平面a与平面
所成角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88929f4ba0851730d5f941d426b87548.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e65a3e478bb87d094e3a0af30dd10ae8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f927d383a6f99b9716b43716822d936.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24bb49fdc6b6bbb2449fdf8a0de769d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f34b6147c651a453311bb492d48f207d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8aecd1f2013b1f9df3feb3574d3b5c34.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/19/4c23791e-935d-441d-8c36-30fbb73e2c84.png?resizew=180)
(1)请在图中画出直线l,写出画法并说明理由
(2)求平面a与平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9836949f7896f7b329ec653225a4c765.png)
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解题方法
2 . 如图的虚线网格纸上小正方形的边长为1,粗实线画出的是某几何体的三视图.在该几何体的直观图中,直线
与
所成角的余弦值为( )
![](https://img.xkw.com/dksih/QBM/2020/2/12/2397569787617280/2398867649388544/STEM/44e3a3fb-c39d-4a59-8295-49617b96307e.png?resizew=260)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://img.xkw.com/dksih/QBM/2020/2/12/2397569787617280/2398867649388544/STEM/44e3a3fb-c39d-4a59-8295-49617b96307e.png?resizew=260)
A.![]() | B.![]() | C.![]() | D.![]() |
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3 . 如图,在长方体
中,
,
,
为
的中点
(1)在所给图中画出平面
与平面
的交线(不必说明理由)
(2)证明:
平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ef676509065322bfc244e59607bb60d.png)
(3)求平面
与平面
所成锐二面角的余弦值
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24bb49fdc6b6bbb2449fdf8a0de769d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8745717601cd14b46c2298919b41b502.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad1a56baf43ffdf67bc8460856e31fec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fbafedc202bd0d86c4dfdece9f8f4fe.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/17/90a20a4f-b105-4e81-a597-ec7f8158ad82.png?resizew=158)
(1)在所给图中画出平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/028856d5101687dd8eaf130846489cfd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ef676509065322bfc244e59607bb60d.png)
(2)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f511b6f2e0072ff616a5b79b0617db7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ef676509065322bfc244e59607bb60d.png)
(3)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/028856d5101687dd8eaf130846489cfd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ef676509065322bfc244e59607bb60d.png)
您最近一年使用:0次