b)Ta có:
\(17^{20}=17^{4.5}=\left(17^4\right)^5=83521^5>71^5\)
c)Ta có:
\(0,3^{20}=\left(0,3^2\right)^{10}=0,09^{10}< 0,1^{10}\)
d)Ta có:
\(\left(\frac{1}{16}\right)^{10}=\left(\frac{1}{2}\right)^{40}\)
\(\left(\frac{1}{8}\right)^{13}=\left(\frac{1}{2}\right)^{39}\)
Vì \(\left(\frac{1}{2}\right)^{40}>\left(\frac{1}{2}\right)^{39}\)
nên \(\left(\frac{1}{16}\right)^{10}>\left(\frac{1}{8}\right)^{13}\)
e)Ta có:
\(3^{21}=3^{20}.3=9^{10}.3\)
\(2^{31}=2^{30}.2=8^{10}.2\)
Vì \(9^{10}.3>8^{10}.2\)
\(\Rightarrow3^{21}>2^{31}\)
