S = 1 + 3 + 32 + 33 + ..... + 32017
\(\Rightarrow\)3S = 3 + 32 + 33 + 34 + ...... + 32018
\(\Rightarrow\)3S - S = (3 + 32 + 33 + 34 + ...... + 32018) - (1 + 3 + 32 + 33 + ..... + 32017)
\(\Rightarrow\)2S = 32018 - 1
\(\Rightarrow\)S = \(\frac{3^{2018}-1}{2}\)
S = 1 + 3 + 3^2 + ... + 3^2017
3S = 3 + 3^2 + 3^3 + ... + 3^2018
3S - S = 2S = ( 3 + 3^2 + 3^3 + ... + 3^2018 ) - ( 1 + 3 + 3^2 = ... + 3^2017 )
2S = 3^2018 - 1
S = 3^2018 - 1 / 2
\(3S=3+3^2+3^3+...+3^{2018}\)
\(3S-S=2S=3+3^2+3^3+...+3^{2018}-1-3-3^2-...-3^{2017}\)
\(2S=3^{2018}-1\)
\(S=\frac{3^{2018}-1}{2}\)
S = 1 + 3 + 32 + ... + 32017
S = 30 + 31 + 32 + ... + 32017
3S = 31 + 32 + 33 +... +32015 + 32016 + 32017 + 32018
3S - S = 32018 - 30
2S = 32018 - 1
S = (32018 - 1 ) : 2
Vậy S = (32018 - 1) :2
