Câu hỏi của Trần Đăng Khoa

Question

Tính 2^0+2^1+2^2+2^2+2^4+......+2^2018

Không Tên · Accepted Answer

Đặt $A=2^0+2^1+2^2+2^3+2^4+....+2^{2018}$

$\Rightarrow$$2A=2^1+2^2+2^3+2^4+2^5+.....+2^{2019}$

$\Rightarrow$$2A-A=\left(2^1+2^2+2^3+...+2^{2019}\right)-\left(2^0+2^1+...+2^{2018}\right)$

$\Rightarrow$$A=2^{2019}-1$

Câu trả lời:

Đặt $A=2^0+2^1+2^2+2^3+2^4+....+2^{2018}$

$\Rightarrow$$2A=2^1+2^2+2^3+2^4+2^5+.....+2^{2019}$

$\Rightarrow$$2A-A=\left(2^1+2^2+2^3+...+2^{2019}\right)-\left(2^0+2^1+...+2^{2018}\right)$

$\Rightarrow$$A=2^{2019}-1$