已知a+b+c=0,求a^2+b^2+c^2+2ab+2bc+2ac是多少?
问题描述:
已知a+b+c=0,求a^2+b^2+c^2+2ab+2bc+2ac是多少?
答
0啊
答
a^2+b^2+c^2+2ab+2bc+2ac
=(a+b+c)^2
=0
答
... 0
答
a^2+b^2+c^2+2ab+2bc+2ac
=(a+b+c)^2
=0
答
a^2+b^2+c^2+2ab+2bc+2ac
=(a^2+b^2+2ab)+c^2+(2ac+2bc)
=(a+b)^2+2c(a+b)+c^2
=(a+b+c)^2
=0