证明:
∵AG⊥BD,∠BAC=90°
∴∠CAG+∠BAG=90°,∠ABF+∠BAG=90°
∴∠ABF=∠CAG
∵AD平分∠BAC,AB=AC
∴∠BAF=∠C=45°
∴△ABF≌△CAE
∴BF=AE