\(A=\dfrac{2}{3.5}+\dfrac{2}{5.7}+\dfrac{2}{7.9}+...+\dfrac{2}{2015.2017}\)
\(=\dfrac{2}{3}-\dfrac{2}{5}+\dfrac{2}{5}-\dfrac{2}{7}+\dfrac{2}{7}-\dfrac{2}{9}+...+\dfrac{2}{2015}-\dfrac{2}{2017}\)
\(=\dfrac{2}{3}-\dfrac{2}{2017}\)
\(=\dfrac{4028}{6051}\)
A=\(\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+...+\dfrac{1}{2015}-\dfrac{1}{2017}\)
=\(\dfrac{1}{3}-\dfrac{1}{2017}\)
= \(\dfrac{2014}{6051}\)
A = \(\dfrac{2}{3.5}\)+ \(\dfrac{2}{5.7}\)+\(\dfrac{2}{7.9}\)+.....+\(\dfrac{2}{2015.2017}\)
= \(\dfrac{1}{3}\)-\(\dfrac{1}{5}\)+\(\dfrac{1}{5}\)-\(\dfrac{1}{7}\)+\(\dfrac{1}{7}\)-\(\dfrac{1}{9}\)+.....+\(\dfrac{1}{2015}\)-\(\dfrac{1}{2017}\)
= \(\dfrac{1}{3}\)- \(\dfrac{1}{2017}\)
= \(\dfrac{2017}{6051}-\dfrac{3}{6051}\)
= \(\dfrac{2014}{6051}\)
Nhớ tick nhé bạn chuẩn đó , nếu bạn chưa hiểu thì nhắn tin mk giảng lại cho nha !
