共50条信息
以正方体\(ABCD-A_{1}B_{1}C_{1}D_{1}\)的棱\(AB\),\(AD\),\(AA_{1}\)所在的直线为坐标轴建立空间直角坐标系,且正方体的棱长为一个单位长度,则棱\(CC_{1}\)中点坐标为\((\) \()\)
如图,四棱柱\(ABCD-A_{1}B_{1}C_{1}D_{1}\)的底面\(ABCD\)是菱形,\(AC\cap BD=0\),\(A_{1}O⊥\)底面\(ABCD\),\(AB=2\),\(AA_{1}=3\).
\((1)\)证明:平面\(A_{1}CO⊥\)平面\(BB_{1}D_{1}D\);
\((2)\)若\(∠BAD=60^{\circ}\),求二面角\(B-OB_{1}-C\)的余弦值.
已知点\(A(-3,1,-4)\),则点\(A\)关于\(x\)轴对称的点的坐标为\((\) \()\)
如图,在四棱锥\(P\)\(\)\(ABCD\)中,底面\(ABCD\)是矩形,\(PA\)\(⊥\)平面\(ABCD\),\(PA\)\(=\)\(AD\)\(=4\),\(AB\)\(=2.\)以\(BD\)的中点\(O\)为球心,\(BD\)为直径的球面交\(PD\)于点\(M\).
\((1)\)求证:平面\(ABM\)\(⊥\)平面\(PCD\);
\((2)\)求直线\(PC\)与平面\(ABM\)所成角的正切值;
\((3)\)求点\(O\)到平面\(ABM\)的距离.
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