有關3OC的精選大全

如圖,在△ABC中,∠ABC=,O為AB邊上一點,且3OB=3OC=2AB,已知PO⊥平面ABC,2DA=2A...
問題詳情:如圖,在△ABC中,∠ABC=,O為AB邊上一點,且3OB=3OC=2AB,已知PO⊥平面ABC,2DA=2AO=PO,且DA∥PO.(1)求*:平面PBD⊥平面COD;(2)求直線PD與平面BDC所成角的正弦值.【回答】(1)*∵OB=OC,又∵∠ABC=,∴∠OCB=,∴∠BOC=.∴CO⊥AB.2分又PO⊥...
熱門標籤