Question

Bài này khó quá mk ko bit làm các bạn chỉ giùm nha

S=2^1+2^2+2^3+2^4+...+2^2017+2^2018

Bạn nào bit chỉ mk nha 

Answer 1

2S=2.(2^1+2^2+2^3+2^4+...+2^2017+2^2018)=2^2+...............2^2019

2S-S=2^2+...............2^2019-(2^1+2^2+2^3+2^4+...+2^2017+2^2018)

S=2^2019-2

Answer 2

\(S=2^1+2^2+2^3+2^4+..+2^{2017}+2^{2018}\)

\(S=2^{2018}+2^{2017}+....+2^4+2^3+2^2+2^1\)

\(2S=2^{2019}+2^{2018}+....+2^5+2^4+2^3+2^2\)

\(\Rightarrow2S-S=2^{2019}-2\)

hay \(S=2^{2019}-2\)