Question

Rezolva Inegalitatia.Va rog!

Answer 1

a^2+b^2+c^2>=ab+bc+ca <=> 2a^2+2b^2+2c^2>=2ab+2bc+2ca <=> (a^2-2ab+b^2)+(b^2-2bc+c^2)+(c^2-2ca+a^2)>=0 <=> (a-b)^2+(b-c)^2+(c-a)^2>=0, adevarat, oricare ar fi a,b,c apartin R.