Question

1+2+2²+2³+2⁴+....2¹⁰⁰ = ?

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Answer 1

Đặt A = \(1+2+2^2+2^3+2^4+....+2^{100}\)

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

= \(2+2^2+2^3+2^4+2^5+...+2^{101}\)

2A - A = \(\left(2+2^2+2^3+2^4+2^5+....+2^{101}\right)-\left(1+2^2+2^3+2^4+...+2^{100}\right)\)

= \(2^{101}-1\)

 

Answer 2

Answer 3

Nếu bạn bt lm r thì ko nên ra câu hỏi nx đâu .

Answer 4

Đặt \(A=1+2+2^2+2^3+2^4+...+2^{100}\) 

\(2A=2+2^2+2^3+2^4+2^5+...+2^{101}\) 

\(2A-A=\left(2+2^2+2^3+2^4+2^5+...+2^{101}\right)-\left(1+2+2^2+2^3+2^4+...+2^{100}\right)\) \(A=2^{101}-1\)