I have to Prove (a+b)^2 + (b+c)^2 + (c+a)^2 >= 4(ab + bc + ac)
I multiplied out both sides and then move everything to the left, but I don't know what I should do after that.
Hello, Nichelle14!
Prove that: .
I multiplied out both sides and then move everything to the left. . . . Not recommended
Multiply out the left side and we have:
. . LHS
Since are real numbers: .
Multiply by
Add to both sides:
. .
. . . . . . . . This is LHS
Therefore: .