a+b+c=0证明ab+bc+ac>=0
问题描述:
a+b+c=0证明ab+bc+ac>=0
答
(a+b+c)^2=0,a^2+b^2+c^2+2ab+2bc+2ac=0.2ab+2bc+2ac=-(a^2+b^2+c^2)
a+b+c=0证明ab+bc+ac>=0
(a+b+c)^2=0,a^2+b^2+c^2+2ab+2bc+2ac=0.2ab+2bc+2ac=-(a^2+b^2+c^2)