在所示的几何体中,底面ABCD是直角梯形,AB‖CD,∠DAB=90°,EA⊥底面ABCD,FD‖EA,EA=AB=2,FD=DC=1,AD=根号2(1)求异面直线BE与AF所成角的余弦值(2)求证:bd⊥面ACE(3)求二面角E-AC-F的余弦值
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![在所示的几何体中,底面ABCD是直角梯形,AB‖CD,∠DAB=90°,EA⊥底面ABCD,FD‖EA,EA=AB=2,FD=DC=1,AD=根号2(1)求异面直线BE与AF所成角的余弦值(2)求证:bd⊥面ACE(3)求二面角E-AC-F的余弦值](/uploads/image/z/12662304-24-4.jpg?t=%E5%9C%A8%E6%89%80%E7%A4%BA%E7%9A%84%E5%87%A0%E4%BD%95%E4%BD%93%E4%B8%AD%2C%E5%BA%95%E9%9D%A2ABCD%E6%98%AF%E7%9B%B4%E8%A7%92%E6%A2%AF%E5%BD%A2%2CAB%E2%80%96CD%2C%E2%88%A0DAB%3D90%C2%B0%2CEA%E2%8A%A5%E5%BA%95%E9%9D%A2ABCD%2CFD%E2%80%96EA%2CEA%3DAB%3D2%2CFD%3DDC%3D1%2CAD%3D%E6%A0%B9%E5%8F%B72%EF%BC%881%EF%BC%89%E6%B1%82%E5%BC%82%E9%9D%A2%E7%9B%B4%E7%BA%BFBE%E4%B8%8EAF%E6%89%80%E6%88%90%E8%A7%92%E7%9A%84%E4%BD%99%E5%BC%A6%E5%80%BC%EF%BC%882%EF%BC%89%E6%B1%82%E8%AF%81%EF%BC%9Abd%E2%8A%A5%E9%9D%A2ACE%EF%BC%883%EF%BC%89%E6%B1%82%E4%BA%8C%E9%9D%A2%E8%A7%92E-AC-F%E7%9A%84%E4%BD%99%E5%BC%A6%E5%80%BC)
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