∵正方形ABCD
∴AD=AB
∠D=∠ABC=90°,∠DAB=90°
又∵AE⊥AF
∴∠EAF=90°
∵∠EAB+∠BAF=90°
∠DAF+∠BAF=90°
∴∠EAB=∠DAF
∵∠ABC=90°
∴∠ABE=180°-90°=90°
∴∠ABE=∠D=90°
在△AEB和△AFD中
∵AD=AB
∠ABE=∠D=90°
∠EAB=∠DAF
∴△AEB全等于△AFD
∴BE=DF
∵正方形ABCD
∴AD=AB
∠D=∠ABC=90°,∠DAB=90°
又∵AE⊥AF
∴∠EAF=90°
∵∠EAB+∠BAF=90°
∠DAF+∠BAF=90°
∴∠EAB=∠DAF
∵∠ABC=90°
∴∠ABE=180°-90°=90°
∴∠ABE=∠D=90°
在△AEB和△AFD中
∵AD=AB
∠ABE=∠D=90°
∠EAB=∠DAF
∴△AEB全等于△AFD
∴BE=DF