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            • 1. 如图,在直四棱柱\(ABCD-A_{1}B_{1}C_{1}D_{1}\)中,底面\(ABCD\)为等腰梯形,\(AB/\!/CD\),\(AB=4\),\(BC=CD=2\),\(AA_{1}=2\),\(E\),\(E_{1}\)分别是棱\(AD\),\(AA_{1}\)的中点.
              \((1)\)设\(F\)是棱\(AB\)的中点,证明:直线\(EE_{1}/\!/\)平面\(FCC_{1}\);
              \((2)\)证明:平面\(D_{1}AC⊥\)平面\(BB_{1}C_{1}\)C.
            • 2.

              如图所示,四边形\(ABCD\)与四边形\(ADEF\)都为平行四边形,\(M\),\(N\),\(G\)分别是\(AB\),\(AD\),\(EF\)的中点\(.\)求证:


              \((1)BE/\!/\)平面\(DMF\);

              \((2)\)平面\(BDE/\!/\)平面\(MNG\).

            • 3. 如图,四边形\(ABCD\)与\(ADEF\)为平行四边形,\(M\),\(N\),\(G\)分别是\(AB\),\(AD\),\(EF\)的中点.

              求证:

              \((1)BE/\!/\)平面\(DMF\);

              \((2)\)平面\(BDE/\!/\)平面\(MNG\).

            • 4.

              如图,四棱锥\(P-ABCD\)的底面\(ABCD\)是菱形,且\(\angle DAB=\dfrac{\pi }{3}\),其对角线\(AC\)、\(BD\)交于点\(O\),\(M\)、\(N\)是棱\(PA\)、\(PB\)上的中点.

              \((1)\)求证:面\(MNO/\!/\)面\(PCD\);

              \((2)\)若面\(PCD\bot \)底面\(ABCD\),\(AB=2\),\(PC=3\),\(PD=\sqrt{19}\),求三棱锥\(M-BON\)的体积.

            • 5.

              在直三棱柱\(ABC—A_{1}B_{1}C_{1}\)中,平面\(α\)与棱\(AB\),\(AC\),\(A_{1}C_{1}\),\(A_{1}B_{1}\)分别交于点\(E\),\(F\),\(G\),\(H\),且直线\(AA_{1}/\!/\)平面\(α.\)有下列三个命题:\(①\)四边形\(EFGH\)是平行四边形;\(②\)平面\(α/\!/\)平面\(BCC_{1}B_{1}\);\(③\)平面\(α⊥\)平面\(BCFE.\)其中正确的命题有

              A.\(①②\)   
              B.\(②③\)   
              C.\(①③\)   
              D.\(①②③\)
            • 6.

              已知\(\alpha{,}\beta\)是相异两平面,\(m{,}n\)是相异两直线,则下列命题中不正确的是 \(({  })\)

              A.若\(m{/\!/}n{,}m{⊥}\alpha\),则\(n{⊥}\alpha\)
              B.若\(m{⊥}\alpha{,}m{⊥}\beta\),则\(\alpha{/\!/}\beta\)
              C.若\(m{/\!/}\alpha{,}\alpha{∩}\beta{=}n\),则\(m{/\!/}n\)
              D.若\(m{⊥}\alpha{,}m{⊂}\beta\),则\(\alpha{⊥}\beta\)
            • 7.

              已知三棱柱\(ABC-A_{1}B_{1}C_{1}\),平面\(β\)截此三棱柱,分别与\(AC\),\(BC\),\(B_{1}C_{1}\),\(A_{1}C_{1}\)交于点\(E\),\(F\),\(G\),\(H\),且直线\(CC_{1}/\!/\)平面\(β.\)有下列三个命题:\(①\)四边形\(EFGH\)是平行四边形;\(②\)平面\(β/\!/\)平面\(ABB_{1}A_{1}\);\(③\)若三棱柱\(ABC—A_{1}B_{1}C_{1}\)是直三棱柱,则平面\(β\)上平面\(A_{1}B_{1}C_{1}.\)其中正确的命题为

              A.\(①②\)
              B.\(①③\)
              C.\(①②③\)
              D.\(②③\)
            • 8. 底面为菱形的直棱柱\(ABCD{-}A_{1}B_{1}C_{1}D_{1}\)中,\(E\)、\(F\)分别为棱\(A_{1}B_{1}\)、\(A_{1}D_{1}\)的中点.

              \((i)\)在图中作一个平面\(\alpha\),使得\(BD{⊂}\alpha\),且平面\(AEF{/\!/}\alpha{,}(\)不必给出证明过程,只要求作出\(\alpha\)与直棱柱\(ABCD{-}A_{1}B_{1}C_{1}D_{1}\)的截面\()\)
              \((ii)\)若\(AB{=}AA_{1}{=}2{,}{∠}BAD{=}60^{{∘}}\),求平面\(AEF\)与平面\(\alpha\)的距离\(d\).
            • 9.

              如图,在直三棱柱\(ABC—A_{1}B_{1}C_{1}\)中,\(∠BAC=90^{\circ}\),\(AB=AC=2\),点\(M\),\(N\)分别为\(A_{1}C_{1}\),\(AB_{1}\)的中点.

              \((1)\)证明:\(MN/\!/\)平面\(BB_{1}C_{1}C\);

              \((2)\)若\(CM⊥MN\),求三棱锥\(M—NAC\)的体积.

            • 10.

              已知\(PA\)垂直于矩形\(ABCD\)所在平面,\(M\),\(N\)分别是\(AB\),\(PC\)的中点.

              \((1)\)求证\(MN/\!/平面PAD \)

              \((2)\)求证:\(MN⊥CD\);

              \((3)\)若平面\(PDC与平面ABCD \)成\(45^{\circ}\)角,求证:\(MN⊥ \)面\(PCD\)

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