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1 . 如图,在三棱柱
中,
分别为
的中点,则下列说法错误的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42c2d86d8daea5e652d99fe1c6bc3f9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c21840e2f00fe67676dd3a90a40dd3a.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
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2024-04-06更新
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3452次组卷
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10卷引用:四川省成都市成华区某校2023-2024学年高三“三诊”数学(文)试题
四川省成都市成华区某校2023-2024学年高三“三诊”数学(文)试题湖南省新高考教学教研联盟2024届高三下学期第二次联考数学试题广东省茂名市高2024届高三下学期高考模拟数学试题(已下线)8.4.1 平面【第三课】“上好三节课,做好三套题“高中数学素养晋级之路福建省三明第一中学2023-2024学年高一下学期期中考试数学试卷海南省海南中学2023-2024学年高一下学期期中考试数学试题黑龙江省大庆市实验中学实验二部2023-2024学年高三下学期阶段考试数学试题河南省信阳高级中学2023-2024学年高一下学期5月期中考试数学试题(已下线)第8.4.1讲 平面-同步精讲精练宝典(人教A版2019必修第二册)湖北省荆州市荆州中学2023-2024学年高一下学期5月月考数学试卷
2 . 如图,
为正三角形,
平面
,
,
为
的中点,
,
.
![](https://img.xkw.com/dksih/QBM/2015/2/10/1571988166696960/1571988172652544/STEM/7ceeca21c96e482ca28e086c28fac2fd.png)
(Ⅰ)求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
平面
;
(Ⅱ)求平面
与平面
所成的锐二面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd936a2405709574af0a73543d94ad9c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19efd943fe98bcea0394795a7bc06f33.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/082f4777d26f09734bfa559e064038fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1642eec556eb252de9c1ab7bb5ca90b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afc09970c72e7921f392bdac2b51fcce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dfb08f6a798dc293f3d8de281190f65e.png)
![](https://img.xkw.com/dksih/QBM/2015/2/10/1571988166696960/1571988172652544/STEM/7ceeca21c96e482ca28e086c28fac2fd.png)
(Ⅰ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(Ⅱ)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/823f4e614dd9290178c2b9c9fd2460a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
您最近一年使用:0次
3 . 如图,在四棱锥P—ABCD中,底面ABCD是边长为4的菱形,且
,菱形ABCD的两条对角线的交点为0,PA=PC,PB=PD,且PO=3.点E是线段PA的中点,连接EO、EB、EC.
![](https://img.xkw.com/dksih/QBM/2012/5/10/1570852891713536/1570852897185792/STEM/f0e02adcc29e4680a3b50e130d347db8.png)
(I)证明:直线OE//平面PBC;
(II)求二面角E-BC-D的大小
![](https://img.xkw.com/dksih/QBM/2012/5/10/1570852891713536/1570852897185792/STEM/7a8ca84c69aa49f691c019f6807feb05.png)
![](https://img.xkw.com/dksih/QBM/2012/5/10/1570852891713536/1570852897185792/STEM/f0e02adcc29e4680a3b50e130d347db8.png)
(I)证明:直线OE//平面PBC;
(II)求二面角E-BC-D的大小
您最近一年使用:0次