在四棱锥
中,底面
是正方形,
与
交于点
,
底面
,
为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/14/e72c41a5-f7bc-409e-96ea-495310a6e805.png?resizew=184)
(1)求证:
∥平面
;
(2)若
,在线段
找一点
,使
平面
,求出
的值.
![](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/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/3f09ad78d4eccd1a9c9ccd3c4af79c79.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/14/e72c41a5-f7bc-409e-96ea-495310a6e805.png?resizew=184)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4734735213b599a9915e1ed91a5d8ce4.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17101383eb0787edaaa35adfcd20d5c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f90c780dac29ff8b7df5881d3b33abab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b664dcf80fed37a8ef4426917b8fb49e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e01375423215809feac6a249e800aaf.png)
更新时间:2020-10-27 15:01:51
|
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解答题-作图题
|
适中
(0.65)
【推荐1】如图,
是三棱锥
侧面
上一点,过点
作一个截面,使得
与
都与截面平行,请作出截面与三棱锥各面的交线,并写出作法.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
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解答题-证明题
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适中
(0.65)
名校
【推荐2】在四棱锥P-ABCD中,底面ABCD是梯形,AB∥DC,AD⊥DC,AB=AD=2,DC=3,平面PDC⊥平面ABCD,E在棱PC上且PE=2EC.
![](https://img.xkw.com/dksih/QBM/2019/5/23/2209859316424704/2209891653713920/STEM/75ef3a52440841ae91d757352da11b1a.png?resizew=214)
()证明:BE∥平面PAD;
(1)若ΔPDC是正三角形,求三棱锥P-DBE的体积.
![](https://img.xkw.com/dksih/QBM/2019/5/23/2209859316424704/2209891653713920/STEM/75ef3a52440841ae91d757352da11b1a.png?resizew=214)
()证明:BE∥平面PAD;
(1)若ΔPDC是正三角形,求三棱锥P-DBE的体积.
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐1】如图,在三棱柱
中,
是正方形
的中心,
,
平面
,且![](https://staticzujuan.xkw.com/quesimg/Upload/formula/866905ae0dcb57c966240c36465e7d56.png)
(Ⅰ)求异面直线
与
所成角的余弦值;
(Ⅱ)求二面角
的正弦值;
(Ⅲ)设
为棱
的中点,点
在平面
内,且
平面
,求线段
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9edc50f7febbc2d5d8dcdc23a3630a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3cf90bac174f02c4552e56df4d910bd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1722a11031cf3668ac4a2abaca280cba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9edc50f7febbc2d5d8dcdc23a3630a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/866905ae0dcb57c966240c36465e7d56.png)
(Ⅰ)求异面直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
(Ⅱ)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24aee5e085257d9a3b6169ac2d65ea00.png)
(Ⅲ)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56f7ba05c54b3de1f4378f7c8eb58328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9edc50f7febbc2d5d8dcdc23a3630a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93cf663ee2bf1ac5c43f4306fa0cf250.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99b16cff607cdc2d69afc70dc778acbb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e69d2b798744645af88a4fa411344a83.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/21/049d8177-7000-4a5f-93c4-3b44abaa3dc6.png?resizew=245)
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解答题-证明题
|
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(0.65)
名校
解题方法
【推荐2】如图所示,
矩形
所在的平面,
分别是
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/18/3ebc2af6-ee27-4b66-b513-c3f99a96fbd1.png?resizew=167)
(1)求证:
平面
;
(2)求证:
.
(3)当
满足什么条件时,能使
平面
成立?并证明你的结论.
![](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/e6670479a0083dd2dfd5ad55b47b1ab6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6cca777c664ecc22e40dff4ccae6b248.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/18/3ebc2af6-ee27-4b66-b513-c3f99a96fbd1.png?resizew=167)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1eaa5e336f830a3e5cd60ff7a756f3ef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aab384f2520d76ed8fa01b31e09c1eea.png)
(3)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55a675310c8ba418e5a59beb7317e21e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93cf663ee2bf1ac5c43f4306fa0cf250.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
您最近一年使用:0次