C = 1+5+52+53+.....+5100
5C = 5+52+53+54+.......+5101
4C = 5C - C = 5101 - 1
=> C = \(\frac{5^{101}-1}{4}\)
C = 1+5+52+53+.....+5100
5C = 5+52+53+54+.......+5101
4C = 5C - C = 5101 - 1
=> C = \(\frac{5^{101}-1}{4}\)
thu gon tong B=5+52+53+54+.......+52012+52013
Hãy thu gon tổng sau ; 1-3+3^2-3^3+3^4-3^5+3^6-..............+3^98-3^99+3^100
rut gon A= 1*4/2*3+2*5/2*4+3*6/4*5+...+98*101/99*100
BT1 : Tịnh tong :
A=2+2^2+2^3+...+2^100
B=5+5^3+...5^20
C=1/12+1/23+1/34+...+1/99000
D=2/1.3+1/3.5+1/5.7+....2/99000
1.Cho tong S=5+8+11+14...
tim so hang thu 100 cua day
2.Tinh tong S=1+2+22+...+210
bai 1) tong cac so sau co chia het cho 2 khong ? 132014+152015
bài 2) tổng các số sau có chia hết cho 5 không ? 1212013+1252014
bai 3 cho tong S= 21+22+23+...+2100
A) viet gon tong S
B) chung to S chia het cho 3
thu gon
a.A=43+6^3+6^4+6^5+...+6^99+6^100
b.Tính B=A-6^101
tong cac luy thua bac 3 cua 3 so la 216Biet 2\5 so thu 1 =3\10 so thu 2 va 5\6 so thu 2=2\3 so thu 3 .Tim 3 so do?
Tinh tong S = 1×2+2×3+3×4+4×5+•••••+99×100