2. $Q \leq \frac{1}{2a^{2}b+2ab^{2}}+\frac{1}{2ab^{2}+2a^{2}b}=\frac{1}{ab(a+b)}$$\frac{1}{a}+\frac{1}{b}=2 \Rightarrow a+b=2ab$ $\Rightarrow Q\leq \frac{1}{2a^{2}b^{2}}$$(a+b)^{2}\geq 4ab \Leftrightarrow (a+b)^{2}\geq2(a+b) \Leftrightarrow a+b\geq2$ $\Leftrightarrow \frac{a+b}{ab}\geq \frac{2}{ab} \Leftrightarrow 2\geq \frac{2}{ab}$ $\Rightarrow ab \geq1$$\Rightarrow Q \leq \frac{1}{2}$ dấu "=" $\Leftrightarrow a=b=1$
2. $Q \leq \frac{1}{2a^{2}b+2ab^{2}}+\frac{1}{2ab^{2}+2a^{2}b}=\frac{1}{ab(a+b)}$$\frac{1}{a}+\frac{1}{b}=2 \Rightarrow a+b=2ab$ $\Rightarrow Q\leq \frac{1}{2a^{2}b^{2}}$$(a+b)^{2}\geq 4ab \Leftrightarrow (a+b)^{2}\geq2(a+b) \Leftrightarrow a+b\geq2$ $\Leftrightarrow \frac{a+b}{ab}\geq \frac{2}{ab} \Leftrightarrow 2\geq \frac{2}{ab}$ $\Rightarrow ab\leq 1 \Rightarrow Q\leq \frac{1}{2}$ dấu "=" $\Leftrightarrow a=b=1$
2. $Q \leq \frac{1}{2a^{2}b+2ab^{2}}+\frac{1}{2ab^{2}+2a^{2}b}=\frac{1}{ab(a+b)}$$\frac{1}{a}+\frac{1}{b}=2 \Rightarrow a+b=2ab$ $\Rightarrow Q\leq \frac{1}{2a^{2}b^{2}}$$(a+b)^{2}\geq 4ab \Leftrightarrow (a+b)^{2}\geq2(a+b) \Leftrightarrow a+b\geq2$ $\Leftrightarrow \frac{a+b}{ab}\geq \frac{2}{ab} \Leftrightarrow 2\geq \frac{2}{ab}$ $\Rightarrow ab
\
geq1
$$\Rightarrow Q
\leq \frac{1}{2}$ dấu "=" $\Leftrightarrow a=b=1$