∵BE,CE分别是△ABC的内角和外角的平分线∴∠DBE=1/2∠ABC∠DCE=1/2∠ACD∵∠ACD=∠ABC+∠A ∠DCE=∠DBE+∠E∴∠E=∠DCE-∠DBE=1/2∠ACD-1/2∠ABC=1/2（∠ACD-∠ABC）又∵∠ACD=∠ABC+∠A∴∠E=1/2（∠ABC+∠A-∠ABC...