∵AB＝AC∴∠B＝∠C.∵FD⊥BC,∴∠C﹢∠DEC＝90° ∠B＋∠F＝90°∵∠DEC＝∠AEF∴∠C＋∠AEF＝90°∵∠B＝∠C∴∠F＝∠AEF∴AE＝AF呵呵。。。怕你。。。所以废话了点。。。新号。。。多多照顾啊！
∵ED⊥BC∴∠FEA=∠DEC=90°-∠C，∠F=90°-∠B∵AB=AC∴∠B=∠C∴∠AEF=∠F∴AF=AE
