a) Ta có :
\(0,3^{20}=\left(0,3^2\right)^{10}=0,09^{10}\)
Do \(0,09< 0,1\Rightarrow0,09^{10}< 1^{10}\)
Vậy \(0,1^{10}>0,3^{20}\)
b) Ta có :
\(9999^{10}=\left(99.101\right)^{10}=99^{10}.101^{10}\)
Lại có : \(99^{20}=99^{10}.99^{10}\)
Vì . \(99^{10}< 101^{10}\Rightarrow99^{10}.99^{10}< 99^{10}.101^{10}\)
Vậy \(99^{20}< 9999^{10}\)