a,Cho A=\(\frac{2+2^2+2^3+...+2^{2017}}{1-2^{2017}}\)
Tinh A.
b,Cho A=\(\frac{1}{2017}+\frac{2}{2017^2}+\frac{3}{2017^3}+...+\frac{2017}{2017^{2017}}+\frac{2018}{2017^{2018}}\)
CMR: A<\(\frac{2017}{2017^2}\)
Mik dang can gap.Giup mik voi.Thanks nhiu^^