= \(\frac{1}{2}\left(\frac{2}{1.3}+\frac{2}{3.5}+....+\frac{2}{2009.2011}\right)\)
= \(\frac{1}{2}\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+....+\frac{1}{2009}-\frac{1}{2011}\right)\)
= \(\frac{1}{2}\left(1-\frac{1}{2011}\right)=\frac{1}{2}.\frac{2010}{2011}=\frac{1005}{2011}\)
1/1.3+1/3.5+1/5.7+...+1/2009.2011
1/1.3+1/3.5+1/5.7+...+1/2009.2011
Tính. 1/1.3+1/3.5+1/5.7+....+1/2009.2011
\(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{2009.2011}\)
tính
\(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{2009.2011}\)
Cho Mình Hỏi : Tính
1/1.3+1/3.5 + 1/5.7+...+ 1/2009.2011
Giúp mình với ạ .!
Tính :
\(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{2009.2011}\)
tính
C=1/1.3+1/3.5+...+1/2009.2011
M= 1/3.5+1/5.7+1/7.9+...+1/2007.2009+1/2009.2011
