(2014?泸州)如图,四边形ABCD内接于⊙O,AB是⊙O的直径,AC和BD相交于点E,且DC2=CE?CA.(1)求
(2014?泸州)如图,四边形ABCD内接于⊙O,AB是⊙O的直径,AC和BD相交于点E,且DC2=CE?CA.(1)求证:BC
(2014?泸州)如图,四边形ABCD内接于⊙O,AB是⊙O的直径,AC和BD相交于点E,且DC
2=CE?CA.
(1)求证:BC=CD;
(2)分别延长AB,DC交于点P,过点A作AF⊥CD交CD的延长线于点F,若PB=OB,CD=
2,求DF的长.