如图,在⊙O中,AB为直径,OC⊥AB,弦CD与OB交于点F,在AB的延长线上有点E,且EF=ED.
— Whose is this book written by Yang Jiang?
— Carol's favorite writer is Yang Jiang. It be hers.
已知单位向量a、b,满足a⊥b,则函数fx=xa+b2(x∈R)( )