证明：因为AB>AC则∠ACB>∠ABC在AB上截取AE=AC,作EF‖AD,交BC于F连接AC交AD于O因为AE=AC,所以AD是三角形AEC的垂直平分线EO=OCDF=CDBF=BD-CDEB=AB-AC因为EF‖AD所以,∠EFB=∠ADF又∠ADF=∠ACD+∠CAD>∠ACD>ABC所以,∠...