CD⊥AB∴△ACB是Rt△∴△ACD∽△ABC,△CBD∽△ABC∠A=∠BCD,∠ABC=∠EMCM是AC的中点∴AM=DM=CD∴∠A=∠ADM,∠DMC=∠MCA∴△ABC∽△ECM∴∠E=∠A∠ADM=∠BDE∴∠E=∠BDE=∠BCD∴BE=BD,DE=CD∵△CBD∽△ABC(已证)∴CD/BD=BC/AC∴BE/DE=BC/AC
