题目内容
∠BCA在平面α内,∠ACB=90°,PC是α的斜线段,PC=4,点P到AC,BC的距离都等于,则PC与α的所成角为
A.75°
B.60°
C.45°
D.30°
(Ⅰ)求证:AC⊥平面BB1C1C;
(Ⅱ)求AB1与平面BB1C1C所成角的正切值;
(Ⅲ)在平面AA1B1B内找一点P,使三棱锥P-BB1C为正三棱锥,并求点P到平面BB1C的距离.