原题可知△AEC全等△AFB
1.∠DAF=∠DAB+∠BAF=∠DAB+∠EAC=∠BAC-∠DAE=45°
∠DBF=∠ABF+∠DBA=∠C+∠DBA=90°
2.DF²=BD²+BF²=BD²+EC²=根号29