解答：证明：（1）∵四边形ABCD内接于⊙O，∴∠BAD=∠DCP．又AB?CD=AD?PC，∴ AB PC ＝ AD CD ．∴△ABD∽△CPD．（2）由（1）得∠ABD=∠P．又AE为切线，AD为弦，∴∠EAD=∠ABP，即∠P=∠EAD．∴AE∥BP．
