证明:在AC上取点F,使AF=AE,连接OF
∵∠B=60
∴∠BAC+∠ACB=180-∠B=120
∵AD平分∠BAC
∴∠BAD=∠CAD=∠BAC/2
∵CE平分∠ACB
∴∠ACE=∠BCE=∠ACB/2
∴∠AOE=∠COD=∠CAD+∠ACE=(∠BAC+∠ACB)/2=60
∴∠AOC=180-∠AOE=120
∵AF=AE,AO=AO
∴△AEO≌△AFO (SAS)
∴OE=OF,∠AOF=∠AOE=60
∴∠COF=∠AOC-∠AOF=120-60=60
∴∠COF=∠COD
∵CO=CO
∴△CDO≌△CFO (ASA)
∴CD=CF
∴AC=AF+CF=AE+CD