Toán Cho M = 5+5^2+5^3+….+5^2020 chứng minh rằng M chia hết o 6ch 25/09/2021 By Isabelle Cho M = 5+5^2+5^3+….+5^2020 chứng minh rằng M chia hết o 6ch
Đáp án: M = 5+5^2+5^3+….+5^2020 =(5+5^2) + (5^3+5^4)+…+(5^2019+5^2020) = (5+5^2)+5^2(5+5^2)+…+5^2018(5+5^2) = 30.1 + 5^2 . 30 + …+ 5 ^2018.30 = 30.(1+5^2+…+5^2018) chia het cho 6 Trả lời
$M=5+5^2+..+5^{2020}$ $⇒M=5(1+5)+…+5^{2019}.(1+5)$ $⇒M=5.6+…+5^{2019}.5$ $⇒6.(5+…+5^{2019}\vdots 6$ Trả lời
Đáp án:
M = 5+5^2+5^3+….+5^2020
=(5+5^2) + (5^3+5^4)+…+(5^2019+5^2020)
= (5+5^2)+5^2(5+5^2)+…+5^2018(5+5^2)
= 30.1 + 5^2 . 30 + …+ 5 ^2018.30
= 30.(1+5^2+…+5^2018) chia het cho 6
$M=5+5^2+..+5^{2020}$
$⇒M=5(1+5)+…+5^{2019}.(1+5)$
$⇒M=5.6+…+5^{2019}.5$
$⇒6.(5+…+5^{2019}\vdots 6$