Question

E=4/13+4/15+4/35+....+4/2015x2017

Giúp nhanh cho mik nhé sáng mai nộp rồi !!!

Answer 1

sửa lại nè :

E = 4/3 + 4/15 + 4/35 + ... + 4/2015.2016

Giai

E = 4/3 + 4/15 + 4/35 + ... + 4/2015.2016

\(E=\frac{4}{1.3}+\frac{4}{3.5}+\frac{4}{5.7}+...+\frac{4}{2015.2017}\)

\(E=4.\left(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{2015.2017}\right)\)

\(E=2.\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{2015}-\frac{1}{2017}\right)\)

\(E=2.\left(1-\frac{1}{2017}\right)\)

\(E=2.\frac{2016}{2017}\)

\(E=\frac{4032}{2017}\)