Câu hỏi của Nấm Lùn

Question

Tính:

A= 2¹⁺2²+2³+...+2⁹⁹⁺2¹⁰⁰

Lung Thị Linh · Accepted Answer

$A=2^1+2^2+2^3+...+2^{99}+2^{100}$

$2A=2^2+2^3+2^4+...+2^{100}+2^{101}$

$2A-A=\left(2^2+2^3+2^4+...+2^{100}+2^{101}\right)-\left(2^1+2^2+2^3+...+2^{99}+2^{100}\right)$

$A=2^{101}-2$

Câu trả lời:

$A=2^1+2^2+2^3+...+2^{99}+2^{100}$

$2A=2^2+2^3+2^4+...+2^{100}+2^{101}$

$2A-A=\left(2^2+2^3+2^4+...+2^{100}+2^{101}\right)-\left(2^1+2^2+2^3+...+2^{99}+2^{100}\right)$

$A=2^{101}-2$

Nguyễn Hải Đăng · Answer

Ta có: A=2^1+2^2+2^3+...+2^99+2^100

=> 2A=2^2+2^3+2^4+...+2^100+2^101 Mà A=2^1+2^2+2^3+.........+2^100

=>2A-A=2^101-2^1

=>1A=2^101-2^1

Câu trả lời:

Ta có: A=2^1+2^2+2^3+...+2^99+2^100

=> 2A=2^2+2^3+2^4+...+2^100+2^101 Mà A=2^1+2^2+2^3+.........+2^100

=>2A-A=2^101-2^1

=>1A=2^101-2^1