A= 1/1.3+1/3.5+1/5.7+.....+1/2013.2015
2A=2/1.3+2/3.5+2/5.7+......+2/2013.2015
A=1/1-1/3+1/3-1/5+1/5-1/7+....+1/2013-1/2015
A=1-1/2015=2014/2015
=>A=2014/2015:2
=>A=2014/4030
I K MK MK K LI 3 K
Tính: \(\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+...+\frac{1}{2013.2015}\)
Chứng minh rằng: 1/1.3 + 1/2.4 + 1/3.5 + 1/4.6 + ...+ 1/2013.2015 + 1/2014.2016 < 3/4
Giúp!!!!!!!!
Cho biểu thức A=1/1.3+1/3.5+1/5.7+...+1/37.39.Hãy so sánh A với 1/2
Tình B= 1.3/3.5+2.4/5.7+3.5/7.9+....+(n-1)(n+1)/(2n-1)/2n+1 plzzzz
Tính giá trị cảu biểu thức A=1/1.3+1/3.5+1/5.7+1/7.9+...+1/2017.2019
tinh a= 1.3+3.5+5.7+...+99.101
1/1.3+1/3.5+1/5.7+...+1/97.99
1/1.3+1/3.5+1/5.7+....+1/(2x-1)(2x+1)=49/99
Tìm x:
|x+1/1.3|+|x+1/3.5|+|x+1/5.7|+...+|x+1/97.99|