Question

\(\frac{1}{4.9}+\frac{1}{9.14}+\frac{1}{14.19}+.....+\frac{1}{44.49}\)

Answer 1

= \(\frac{1}{4}\)-\(\frac{1}{9}\)+\(\frac{1}{9}\)-\(\frac{1}{14}\)+\(\frac{1}{14}\)-\(\frac{1}{19}\)+... + \(\frac{1}{44}\)-\(\frac{1}{49}\)

= \(\frac{1}{4}\)-\(\frac{1}{49}\)

= \(\frac{45}{196}\)

ai tốt bụng thì tk cho mk nha, mk đg âm điểm nè huhu