已知a-b=2,a-c=½,求a方+b方+c方-ab-ac-bc
问题描述：
已知a-b=2,a-c=½,求a方+b方+c方-ab-ac-bc
答
∵a-b=2,a-c=½,∴两式相减得：c-b=3/2原式=½{2a²+2b²+2c²-2ab-2ac-2bc}=½{（a-b)²+(a-c)²+(b-c)²}=½{（4+1/4+9/4}=3.25∞ ①②③④⑤√ λμξ⊙°³π²...