$$\frac{4+\sqrt{2}}{2+\sqrt{2}}=a-\sqrt{b}$$
$b=\left(-a+3-\sqrt{2}\right)^{2}$
$-\left(-a+3-\sqrt{2}\right)\geq 0$
$a=\sqrt{b}+3-\sqrt{2}$
$b\geq 0$