问题描述: 一道超难的几何题 1个回答 分类:数学 2014-09-25 问题解答: 我来补答 用反证法(也可说是同一法).∵∠A=∠A,AD=AE∴要证△ADC≌△AEB,只需证AB=AC假设AB≠AC,那么AB<AC或AB>AC当AB<AC时在AC上取一点C'使AB=AC',显然C'在线段EC上.连结DC'交OE于O',连结CO'∵∠A=∠A,AD=AE,AC'=AB∴△ADC‘≌△AEB∴∠AC'D=∠ABE再加上∠DO'B=∠EO'C’,DB=AB-AD=AC'-AE=EC'∴△DO'B≌△EO'C’∴O'B=O'C'∴O'B-OB=O'C'-OC,即O'O=O'C'-OC∴O'O+OC=O'C'但∠AED是锐角∴∠DEC是钝角,∠O'C'C>∠DEC也是钝角∴∠O'C'C>∠O'CC'∴O'O+OC>O'C>O'C',矛盾!同理,当AB>AC也能推出矛盾.∴假设不成立,AB=AC∴△ADC≌△AEB 展开全文阅读