证明：∵∠ACB=90º∴∠CAE+∠AEC=90º∵CD是高∴∠ADC=90º∴∠DAF+∠AFD=90º∵AE平分∠CAB∴∠CAE=∠DAF∴∠AEC=∠AFD∵∠CFE=∠AFE∴∠AEC=∠CFE∴CF=CE
