\[\frac{a^{2} + 3}{\sqrt{a^{2} + 2}} \geq 2\ \]
\[a^{2} + 3 > 0\ \ \ \ \]
\[\sqrt{a^{2} + 2} > 0\]
\[\left( \frac{a^{2} + 3}{\sqrt{a^{2} + 2}} \right)^{2} \geq 4\]
\[\frac{a^{4} + 6a^{2} + 9 - 4a^{2} - 8}{a^{2} + 2} \geq 0\]
\[\frac{a^{4} + 2a^{2} + 1}{a^{2} + 2} \geq 0\]
\[\frac{\left( a^{2} + 1 \right)^{2}}{a^{2} + 2} \geq 0\]
\[\left( a^{2} + 1 \right) > 0;\ \ \]
\[a^{2} + 2 > 0 \Longrightarrow верно.\]