若△ABC的三边为a,b,c.且a,b,c满足a2+b2+c2-ab-ac-bc=0.判断△ABC的形状.

问题描述:

若△ABC的三边为a,b,c.且a,b,c满足a2+b2+c2-ab-ac-bc=0.判断△ABC的形状.

等边三角形
同时扩大2倍
2a^+2b^+2c^-2ab-2ac-2bc=0
(a-b)^+(a-c)^+(b-c)^=0
a=b=c