∠AEC = 20°
设D点是AC的延长线上的点,CE是∠BCD的角平分线
∴∠CDE = ∠ECB = ∠DCB/2
∵AE是∠BAC的角平分线
∴∠BAE = ∠EAC = ∠BAC/2
∴∠DCB = ∠B + ∠CAB =40°+∠CAB.①
∵∠DCE = ∠E + ∠EAC
∴2∠DCE = 2∠E + 2∠EAC = 2∠E + ∠CAB.②
①=②
∴2∠E = 40°
∴∠E = 20°