Tính tổng S = 1 + 2 + 2^2 + 2^3 + 2^4 + + 2^100

2 bình luận về “Tính tổng S = 1 + 2 + 2^2 + 2^3 + 2^4 + + 2^100”

1. S=1+2+2^2+2^3+…+2^100

   => 2S=2+2^2+2^3+2^4+…+2^101

   => 2S-S=S

   =(2+2^2+2^3+2^4+…+2^101)-(1+2+2^2+2^3+…+2^100)

   =2^101-1

   Vậy S=2^101-1

   $\\$

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   Trả lời
2. S = 1 + 2 + 2^2 + 2^3 + 2^4 + …..+ 2^100

   =>2S=2+2^2+2^3+2^4+2^5+…+2^101

   =>2S-S=2+2^2+2^3+2^4+2^5+…+2^101-(1 + 2 + 2^2 + 2^3 + 2^4 + ……+ 2^100)

   =>S=2+2^2+2^3+2^4+2^5+…+2^101-1 – 2 – 2^2 – 2^3 – 2^4 -…… – 2^100

   =>S=2^101-1

   Vậy S=2^101-1

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