
Re: proof of an inequality
Posted:
Apr 23, 2013 12:11 PM


Okey, I guess I got it. Let n=2,
x1^2+x2^2>=((x1+x2)^2)/4
==>4(x1^2+x2^2)>=(x1+x2)^2 ==>3(x1^2+x2^2)>=2x1x2
if x1=x2, it is obvious it holds,
if x1 is not equal x2, then one is greater than other . Let say x1>x2
Then x1^2>x1x2. I guess it is easy to apply n variable case. Thanks alot.

