证明：∵等边△ABC∴AB＝AC＝BC，∠ABC＝∠BAC＝∠ACB＝60∵BD＝AE，AD＝AB-BD，CE＝AC-AE∴AD＝CE∴△BCE全等于△CAD∴∠ACD＝∠CBE∵∠ACD+∠BCD＝∠ABC＝60∴∠COE＝∠CBE+∠BCD＝60∵EF⊥CD∴OE＝2OF
