Question

圆内接三角形ABC中,AB=AC,D是BC边上一点,E是直线AD和三角形ABC外接圆的交点,AE过不过圆心O

Answer 1

证明：（1）连接BE,∵AB=AC,∴∠ABC=∠C．∵∠E=∠C,∴∠ABC=∠E．∵∠BAE=∠DAB,∴△ABE∽△ADB．∴AB：AD=AE：AB．（2分）∴AB2=AD•AE．（4分）（2）成立．（5分）∵AB=AC,∴∠ABC=∠ACB．∵∠EBD=∠DBE,∠A...