\(\left(x-2\sqrt{xy}+y\right)+2y-2\sqrt{x}+1\)
<=>\(\left(\sqrt{x}-\sqrt{y}\right)^2-2\left(\sqrt{x}-\sqrt{y}\right)+1+2y-2\sqrt{y}\)
<=>\(\left(\sqrt{x}-\sqrt{y}-1\right)^2+2\left(y-\sqrt{y}+\frac{1}{2}-\frac{1}{2}\right)\)
<=>\(\left(\sqrt{x}-\sqrt{y}-1\right)^2+2\left(\sqrt{y}-\frac{1}{2}\right)^2-1\)
=>\(A\ge-1\)
dấu bằng xảy ra <=>....
Tick cho mình nha