\(\sqrt{20+\sqrt{20+...+\sqrt{20}}}< \sqrt{20+\sqrt{20+...+\sqrt{20+\sqrt{25}}}}=5\)
Và:\(\sqrt[3]{24+\sqrt[3]{24+...+\sqrt[3]{24}}}< \sqrt[3]{24+\sqrt[3]{24+...+\sqrt[3]{24+\sqrt[3]{27}}}}=3\)
Nên \(T=\sqrt{20+\sqrt{20+...+\sqrt{20}}}+\sqrt[3]{24+\sqrt[3]{24+...+\sqrt[3]{24}}}< 8\)(2).Từ (1) và (2), ta có: \(7< T< 8\)đpcm