如图所示在四棱锥P_ABCD中AB⊥平面PAD,AB∥CD,PD=AD,E是PB的中点,F是DC上的点,且DF=1/2AB,PH为三角形PAD(1)证:PH垂直平面ABCD(2)若PH=1,AD=根号2,FC=1,求三棱锥E-BCF的体积(3)证:EF垂直平面PAB
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![如图所示在四棱锥P_ABCD中AB⊥平面PAD,AB∥CD,PD=AD,E是PB的中点,F是DC上的点,且DF=1/2AB,PH为三角形PAD(1)证:PH垂直平面ABCD(2)若PH=1,AD=根号2,FC=1,求三棱锥E-BCF的体积(3)证:EF垂直平面PAB](/uploads/image/z/1818490-58-0.jpg?t=%E5%A6%82%E5%9B%BE%E6%89%80%E7%A4%BA%E5%9C%A8%E5%9B%9B%E6%A3%B1%E9%94%A5P_ABCD%E4%B8%ADAB%E2%8A%A5%E5%B9%B3%E9%9D%A2PAD%2CAB%E2%88%A5CD%2CPD%3DAD%2CE%E6%98%AFPB%E7%9A%84%E4%B8%AD%E7%82%B9%2CF%E6%98%AFDC%E4%B8%8A%E7%9A%84%E7%82%B9%2C%E4%B8%94DF%3D1%2F2AB%2CPH%E4%B8%BA%E4%B8%89%E8%A7%92%E5%BD%A2PAD%EF%BC%881%EF%BC%89%E8%AF%81%EF%BC%9APH%E5%9E%82%E7%9B%B4%E5%B9%B3%E9%9D%A2ABCD%EF%BC%882%EF%BC%89%E8%8B%A5PH%3D1%2CAD%3D%E6%A0%B9%E5%8F%B72%2CFC%3D1%2C%E6%B1%82%E4%B8%89%E6%A3%B1%E9%94%A5E%EF%BC%8DBCF%E7%9A%84%E4%BD%93%E7%A7%AF%EF%BC%883%EF%BC%89%E8%AF%81%EF%BC%9AEF%E5%9E%82%E7%9B%B4%E5%B9%B3%E9%9D%A2PAB)
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