A=...=(1-$\frac{1}{\frac{2.3}{2}}$)(1-$\frac{1}{\frac{3.4}{2}}$)(1-$\frac{1}{\frac{4.5}{2}}$) .... (1-$\frac{1}{\frac{2015.2016}{2}}$)
A=(1-$\frac{2}{2.3}$)(1-$\frac{2}{3.4}$)(1-$\frac{2}{4.5}$)...(1- $\frac{2}{2015.2016}$) (1-$\frac{1}{\frac{2015.2016}{2}}$)
A=$\frac{4}{2.3}$ .$\frac{10}{3.4}$ .$\frac{18}{4.5}$.... $\frac{4062238}{2015.2016}$
A=$\frac{1.4}{2.3}$ .$\frac{2.5}{3.4}$ .$\frac{3.6}{4.5}$.... $\frac{2014.2017}{2015.2016}$
A=$\frac{(1.2.3....2014)(4.5.6.....2017)}{(1.2.3....2015)(3.4.5....2016)}$
A=$\frac{2017}{2015.3}$ = $\frac{2017}{6045}$
vậy.....
Cho mk xin ctlhn nha, thanks
