Question

Tính tổng:

2/1.3+2/3.5++2/5.7+....+2/153.155

Answer 1

\(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+...+\frac{2}{153.155}\)

\(=1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{153}-\frac{1}{155}\)

\(=1-\frac{1}{155}\)

\(=\frac{154}{155}\)

~Study well~

#JDW

Answer 2

\(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+.......+\frac{2}{153.155}\)

\(=1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+.......+\frac{1}{153}-\frac{1}{155}\)

\(=1-\frac{1}{155}\)

\(=\frac{154}{155}\)