A:相同
B:不同
C:相似
— I have great ____ in finishing the work by myself. Could you help me?
— No problem.
(Ⅰ)证明:CD⊥AE;
(Ⅱ)证明:PD⊥平面ABE;
(Ⅲ)求二面角A﹣PD﹣C的正切值.