Tính tổng A = \(\frac{2}{1.4}\)+ \(\frac{2}{4.7}\)+ \(\frac{2}{7.10}\)+ ... + \(\frac{2}{97.100}\)
1. Tính nhanh các tổng sau :
a) 1/5.6 +1/6.7+1/7.8+...+1/24.25
b) 2/1.3+2/3.5+2/5.7+...+2/99.101
c) 3/1.4+3/4.7+...+3/2002.2005
d) 5/2.7+5/7.12+...+5/1997.2002
tính
1/1.4+1/4.7 +1/7.10 +.....+1/31.34
=
Bài 1 : Tính nhanh
a, 0,36 .350 + 1,2 .20 . 3 + 9 . 4 . 4,5
b, B = 2015.2016-5/2015.2015+2010
c, C = 2/1.3 + 2/3.5 + 2/5.7 + .......+ 2/69.71+ 2/71.73
d, D= (1+1/2) . ( 1+1/3) . (1+1/4) ...... (1+1/2017) . (1+1/2018)
e, E=1/4.5 + 1/5.6 + 1/6.7+........+1/79.80+1/80.81
f, F=3/2.3 + 3/3.4 + 3/4.5 + .......+ 3/99.100
g, G= 5/1.4 + 5/4.7 + 5/7.10 + .......+5/61.64
nhanh nha , mk cần gấp
C= 1/1.4+1/4.7+1/7.11+...+1/994.997+1/997.1000
Giúp tui với
\(A=1.4+4.7+7.10+.....+91.94=?\)
E = 1/(1.4) + 1/(4.7) + ... + 1/(97.100)
F = 3/(1.5) + 3/(5.9) + ... + 3/(74.101)
\(\frac{5}{1.4}+\frac{5}{4.7}+\frac{5}{7.10}+...+\frac{5}{27.30}\)
\(\dfrac{1}{1.4}+\dfrac{1}{4.7}+\dfrac{1}{7.10}+\dfrac{1}{10.13}+...+\dfrac{1}{x.\left(x+3\right)}=\dfrac{34}{103}\)
Tìm x