名校
1 . 如图,在边长为4的正三角形ABC中,D,E,F分别为各边的中点,G,H分别为DE,AF的中点,将
沿DE,EF,DF折成正四面体
,则在此正四面体中,下列说法正确的是______ .
![](https://img.xkw.com/dksih/QBM/2018/12/10/2093856129302528/2095725079232512/STEM/4afb2f7b-c5e0-48b7-a728-2dc40128daf4.png)
异面直线PG与DH所成的角的余弦值为
;
;
与PD所成的角为
;
与EF所成角为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e428e7a09732be85c1224e9c8f6a71c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1712e74c9af60c68f70c9ab452ee83c7.png)
![](https://img.xkw.com/dksih/QBM/2018/12/10/2093856129302528/2095725079232512/STEM/4afb2f7b-c5e0-48b7-a728-2dc40128daf4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c512c047783c07da1d4f4455a4033ef5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d0e7bfbd56fe73dfe04c04da749d942.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afecd7fccd41e1ea29866bf5e4ecd5a0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d9d32b26af27d44067ea12c3dab4362.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe8140a38ee6b0b28a5b661f8b1f3d5e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc97902671846dedfd75506a5e61ca93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fe8dc472dade6cea6943164792ab532.png)
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2018-12-13更新
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3卷引用:【全国百强校】黑龙江省哈尔滨六中2018-2019学年高二(上)期中考试数学(文)试题
【全国百强校】黑龙江省哈尔滨六中2018-2019学年高二(上)期中考试数学(文)试题(已下线)专题8-4 立体几何中求角度、距离类型-2022年高考数学毕业班二轮热点题型归纳与变式演练(全国通用)宁夏回族自治区银川一中2022届高三一模数学(理)试题