H = 5 + 52 + 53 + …..+ 52014 + 52015

2 bình luận về “H = 5 + 52 + 53 + …..+ 52014 + 52015”

1. @YinggAnn

   H = 5 + 5^(2) + 5^(3) + … + 5^(2014) + 5^(2015)

   5H = 5^(2) + 5^(3) + … + 5^(2014) + 5^(2015) + 5^(2016)

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   5H – H = 0 – 5 + 5^(2016)

   4H = 5^(2016) – 5

   H = (5^(2016) – 5)/4

   Vậy H = (5^(2016)-5)/4.

    

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2. Ta có: H = 5 + 5^2 + 5^3 + … + 5^(2014) + 5^(2015)

   => 5H = 5^2 + 5^3 + 5^4 + … + 5^(2015) + 5^(2016)

   => 5H – H = (5^2 + 5^3 + 5^4 + … + 5^(2015) + 5^(2016)) – (5 + 5^2 + 5^3 + … + 5^(2014) + 5^(2015))

   => 4H = 5^(2016) -5

   => H = (5^(2016) – 5)/4

   Vậy H = (5^(2016) – 5)/4

   $#duong612009$

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