\(P=5^0+5^1+5^2+...+5^{2016}\)
\(5P=5+5^2+...+5^{2017}\)
\(\Rightarrow5P-P=5^{2017}-1\)
\(\Rightarrow P=\frac{5^{2017}-1}{4}\)
\(\Rightarrow Q-P=\frac{5^{2017}}{4}-\frac{5^{2017}-1}{4}=\frac{1}{4}\)
P = 5^0+5^1+5^2+..+5^2016
5P = 5^1+5^2+5^3+...+5^2017
5P-P = (5^1+5^2+5^3+...+5^2017) - (5^0+5^1+5^2+..+5^2016)
4P = 5^1+5^2+5^3+...+5^2017-5^0-5^1-5^2-...-5^2016
4P = 5^2017-1
P = (5^2017-1):4
=> Q-P = 5^2017:4 - (5^2017-1) : 4
= (5^2017 - 5^2017 -1) : 4
= (-1) : 4 = -1/4
Vậy...
Chúc em học tốt!!!
Q - P = 52017 : 4 - (52017-1):4
= (52017 - 52017 + 1) : 4
= 1 : 4 = 1/4
Vậy...
Nãy mình quên đổi dấu!!!
