共50条信息
如图,正三棱柱\(ABC-A_{1}B_{1}C_{1}\)的底面边长是\(2\),侧棱长是\(\sqrt{3}\),\(D\)是\(AC\)的中点.
\((\)Ⅰ\()\)求证:\(B_{1}C/\!/\)平面\(A_{1}BD\);
\((\)Ⅱ\()\)求二面角\(A_{1}-BD-A\)的大小;
\((\)Ⅲ\()\)在线段\(AA_{1}\)上是否存在一点\(E\),使得平面\(B_{1}C_{1}E⊥\)平面\(A_{1}BD\),若存在,求出\(AE\)的长;若不存在,说明理由.
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