14-15高三上·浙江温州·期中
解题方法
1 . 如图所示,在四棱锥P-ABCD中,底面ABCD为菱形,PA⊥平面ABCD,∠ABC=60°,E,F分别是BC,PC的中点.
![](https://img.xkw.com/dksih/QBM/2018/9/8/2027824454631424/2045581426794496/STEM/873e917bc33842f0a6775ac505305a13.png?resizew=117)
(1)证明:AE⊥PD;
(2)若AB=2,PA=2,求二面角E-AF-C的余弦值.
![](https://img.xkw.com/dksih/QBM/2018/9/8/2027824454631424/2045581426794496/STEM/873e917bc33842f0a6775ac505305a13.png?resizew=117)
(1)证明:AE⊥PD;
(2)若AB=2,PA=2,求二面角E-AF-C的余弦值.
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2018-10-03更新
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1035次组卷
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6卷引用:2015-2016学年青海省西宁十四中高二期中考试数学试卷