So sánh :\(3\sqrt{5}+2\sqrt{10}\)
\(2\sqrt{10}=\left(2.\sqrt{2}\right).\sqrt{5}\)
Ta có : \(\sqrt{2}< \sqrt{2,25}\)
\(\Rightarrow\sqrt{2}< 1,5\)
\(\Rightarrow2.\sqrt{2}< 2.1,5\)
\(\Rightarrow2.\sqrt{2}< 3\)
\(\Rightarrow3\sqrt{5}>\left(2.\sqrt{2}\right).\sqrt{5}\)
\(\Rightarrow3\sqrt{5}>2\sqrt{10}\)