如图,在四面体ABCD中,平面ABC⊥ACD,AB⊥BC,AD=CD,∠CAD=30° (Ⅰ)若AD=2,AB=2BC,求四面体ABCD的体积. (Ⅱ)若二面角C﹣AB﹣D为60°,求异面直线AD与BC所成角的余弦值.
试题篮