# Algebraic proof

• December 15th 2009, 09:55 AM
Detanon
Algebraic proof
How do i prove this?
If x > 0, y > 0, prove that x + y ≥ 2√¯¯xy.
Thanks.
• December 15th 2009, 10:33 AM
Plato
Quote:

Originally Posted by Detanon
How do i prove this?
If x > 0, y > 0, prove that x + y ≥ 2√¯¯xy.
Thanks.

$(a-b)^2\ge 0$
$a^2-2ab+b^2\ge 0$
Let $a=\sqrt{x}~\&~b=\sqrt{y}$