c. 99^20 và 9999^10
Ta có : \(99^{20}=99^{2.10}=\left(99^2\right)^{10}=9801^{10}\)
Ta thấy : \(9801^{10}< 9999^{10}\)
\(\Rightarrow99^{20}< 9999^{10}\)
a . Ta có : \(8^{51}>8^{50}=8^{2.25}=\left(8^2\right)^{25}=64^{25}\)
Ta thấy : \(64^{25}>48^{25}\)
\(\Rightarrow48^{25}< 8^{51}\)
b.Ta có : \(\left(0,5\right)^{201}>\left(0,5\right)^{200}=\left(0,5\right)^{2.100}=\left(0,5^2\right)^{100}=\left(0,25\right)^{100}\)
Ta thấy : \(\left(0,25\right)^{100}< \left(0,3\right)^{100}\)
\(\Rightarrow\left(0,3\right)^{100}>\left(0,5\right)^{201}\)