12 /1.2 . 22/2.3 . 32/3.4 ... 9992/999.1000
= 1.1/1.2 . 2.2/2.3 . 3.3/3.4........... 999.999/999.1000
= 1/2. 2/3 . 3.4.....999/1000
= 1/1000
12 /1.2 . 22/2.3 . 32/3.4 ... 9992/999.1000
= 1.1/1.2 . 2.2/2.3 . 3.3/3.4........... 999.999/999.1000
= 1/2. 2/3 . 3.4.....999/1000
= 1/1000
Tính : S = 1.2 + 2.3 + 3.4 + ..... + 999.1000
1/1.2+1/2.3+1/3.4+......+1/999.1000
12 /1.2 . 22 /2.3 . 32 /3.4 . 42 /4.5 .52 /5.6 làm thế nào mọi người giúp với ạ
Bài 1
A=1.2+2.3+3.4+....+151.152
B=1.3+3.5+5.7+...+2023.2025
C=2.4+4.6+...+2024.2026
D=1.2+3.4+...+200.202
M=12+22+...+20242
N=13+23+...+1003
Q=13+23+...+20243
R=12+22+...+2003
1 . Tính : 20 ^2 + 22^2 + 24^2 + ...... + 48 ^2 + 50^2
2 . Cho N thuộc N * . Tính tổng
n^2 + ( n +2 ) ^2 + ( n + 4 )^2 + ......... + n +100 ^ 2
3 . Tính : 1.2 + 2.3 + 3.4 + 4.5 + ......... + 999.1000
Tính
a)\(\left(\frac{3}{4}+\frac{-7}{2}\right).\left(\frac{2}{11}+\frac{12}{22}\right)\)
b) \(\frac{1^2}{1.2}.\frac{2^2}{2.3}.\frac{3^2}{3.4}.....\frac{999^2}{999.1000}\)
c) \(\frac{1}{30}+\frac{1}{42}+\frac{1}{56}+....+\frac{1}{132}\)
(1.2)2 / ( 2.3)2 . (3.4)2/ (4.5)2 .... (999.1000)2 / (1000.1001)2
tính
a, 1/1.2+1/2.3+1/3.4+....+1/999.1000
b, B= 1/2.4+1/4.6+1/6.8+1/8.10
Tính:
a) A = \(\dfrac{1}{1.2}\) + \(\dfrac{1}{2.3}\) + \(\dfrac{1}{3.4}\) +...+ \(\dfrac{1}{998.999}\) + \(\dfrac{1}{999.1000}\)
b) B = \(\dfrac{1}{1.6}\) + \(\dfrac{1}{6.11}\) + \(\dfrac{1}{11.16}\) +...+ \(\dfrac{1}{495.500}\)
c) C = \(\dfrac{1}{1.2.3}\) + \(\dfrac{1}{2.3.4}\) + \(\dfrac{1}{3.4.5}\) +...+ \(\dfrac{1}{998.999.1000}\)
(Mong mn giúp ạ)