Đáp án:
Giải thích các bước giải:
#Nothing
C= 1/3+ 1/3^2 +...+1/3^2020 +1/3^2021
=> 1/3C= 1/3^2 +1/3^3 +.....+1/3^2021+ 1/3^2022
=> 1/3C-C=( 1/3^2 +1/3^3 +.....+1/3^2021+ 1/3^2022 )-(1/3+ 1/3^2 +...+1/3^2020 +1/3^2021 )
-2/3C= 1/3^2022 -1/3
=> C=( 1/3^2022 -1/3 ).(-3/2)
Nocopy
@gladbach