Toán Lớp 6: : A = 2 + 2^2 + 2^3+…+ 2^100
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Toán Lớp 6: : A = 2 + 2^2 + 2^3+…+ 2^100
Comments ( 2 )
Giải đáp:
Lời giải và giải thích chi tiết:
$A=2 + 2^2 +2^3+…..+ 2^100$
$2A=2^2 + 263 + 2^4 + … + 2^ 101$
$2A-A =(2^2+2^3+2^4+…+2^100)-(2^2+^3+…+2^100)$
$A=2^101-2$
$A=0^101$
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Giải đáp:
Ta có: A = 2 + 2^2 + 2^3+…+ 2^100
2.A = 2 . ( 2 + 2^2 + 2^3+…+ 2^100 )
= 2^2 + 2^3 + 2^4+…+ 2^101
=> 2.A – A = (2^2 + 2^3 + 2^4+…+ 2^101) – (2 + 2^2 + 2^3+…+ 2^100)
A = 2^101 – 2