共50条信息
棱长为\(2\)的正方体\(ABCD-A_{1}B_{1}C_{1}D_{1}\)中,\(E\)为棱\(CC_{1}\)的中点,点\(P\),\(Q\)分别为面\(A_{1}B_{1}C_{1}D_{1}\)和线段\(B_{1}C\)上的动点,则\(\triangle PEQ\)周长的最小值为
如图,在长方体\(ABCD-A_{1}B_{1}C_{1}D_{1}\)中,\(AB=AD=1\),\(AA_{1}=2\),一只蚂蚁沿侧面\(CC_{1}D_{1}D\)从点\(C\)出发,经过棱\(DD_{1}\)上的一点\(M\)到达点\(A_{1}\),当蚂蚁所走的路径最短时.
\((1)\)求\(B_{1}M\)的长;
\((2)\)求证:\(B_{1}M⊥\)平面\(MAC\).
如图所示是正方体的平面展开图\(.\)在正方体中,下列结论正确的序号是
\(①BM\)与\(ED\)平行;
\(②CN\)与\(BE\)是异面直线;
\(③CN\)与\(BM\)成\(60^{\circ}\)角;
\(④DM\)与\(BN\)垂直.
若母线长为\(1\)的圆锥的侧面展开图的圆心角等于\(\dfrac{4\pi}{3}\),则该圆锥的体积为____\(.\)
进入组卷