证明:∵AC=BD,
∴AB=DC.
∵AE=DF,EA⊥AD,FD⊥AD,
∴∠A=∠D=90°.
∴在△ABE和△DCF中,
AB=DC,∠A=∠D,AE=DF,
∴△ABE≌△DCF(SAS),
∴∠ABE=∠DCF,
∴∠EBD=∠FCA,
∴BE ∥ CF.
证明:∵AC=BD,
∴AB=DC.
∵AE=DF,EA⊥AD,FD⊥AD,
∴∠A=∠D=90°.
∴在△ABE和△DCF中,
AB=DC,∠A=∠D,AE=DF,
∴△ABE≌△DCF(SAS),
∴∠ABE=∠DCF,
∴∠EBD=∠FCA,
∴BE ∥ CF.