∵CE是三角形ACD的中线
∴AE=ED
∵AC=CD CE=CE
∴△AEC全等于△DEC
∴∠ACE=∠DCE=∠ACD/2 ∠AEC=∠DEC
∵CF平分角ACB
∴∠ACF=∠ACB/2
∴∠FCE=∠ACE+∠ACF=∠ACD/2+∠ACB/2=∠ACB/2=180/2=90
∴CE⊥CF
∵∠AEC+∠DEC=180
∴∠AEC=∠DEC=90
∴CE⊥AD
∵CE⊥CF
∴AD||CF