5A=5(1+5+52+...+5200)
5A=5+52+...+5201
5A-A=(5+52+...+5201)-(1+5+52+...+5200)
4A=5201-1
A=(5201-1)/4
5A=5(1+5+52+...+5200)
5A=5+52+...+5201
5A-A=(5+52+...+5201)-(1+5+52+...+5200)
4A=5201-1
A=(5201-1)/4
a, 1-2+3-4+5-6+....+2021-2022
b, 1-6+2-7+3-8+4-9+.......+35-40
c, -1+2-3+4-5+6-.........-2021+2022
d, 1-4+2-5+3-6+.....+197-200
e, -1-2-3-4-5-....-199-200
G=1-5+5^2-5^3+5^4-.....-5^199-5^200
tính tổng
B= 7-7 mu 4 + 7 mu 4 -........+7 mu 301
A = 1 + 5 mũ 2 + 5 mu 4 + 5 mu 6 +.....+5 mu 200
tính
A= 1/7+1/7mu 2 + 1/7 mu 3+......+1/7mu 100
B=-4/5+4/5 mu 2 - 4/5 mu 3 + ....+4/5mu 200
tính A=25 mũ 8 + 25 mũ 4 + 25 mu 20 +......+25 mu 4 +1 / 25 mu 20 + 25 mu 28 + 25 mu 26 +.....= 25 mu 2 +1
A=1+7+72+73+...7200
B=51+53+55+57+...5101
C=1-5+52-53+54-...+580+581+582
D=1+a+a2+a3+...+an
Bài 1.Tìm x
a,210-5x=200
b,210-5(x-10)=200
c,450:[41-(2x-5)]=3^2.5
d,350:x+10=20
e,36:(x-5)=2^2
f,[3.(70-x)+5]:2=46
A=3+32+33+34+...+3300
B=5+52+53+54+...+5200
1 Chứng minh
a) A= (-1/5)^0 + (-1/5)^1 + (-1/5)^2 + ..........+(-1/5)^2014 < 5/6
b) B= 1/101 + 1/102 + 1/103 + ....+ 1/200 < 3/4
C= 1 + 5 mũ 2 + 5 mũ 3 + 5 mũ 4 +. . .+ 5 mũ 200
Bài 1: tính tổng
a ) a=3-3^2+3^3_3^4+...+3^99-3^100
b) B=1+5^2+5^4+5^6+...+5^200
c) C=7-7^4+7^7-...+7^301