Gọi \(A=\frac{5}{4.6}+\frac{5}{6.8}+\frac{5}{8.10}+...+\frac{5}{298.300}\)
\(\Rightarrow A=5\left[\frac{1}{2}\left(\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+...+\frac{1}{298}-\frac{1}{300}\right)\right]\)
\(\Rightarrow A=\frac{5}{2}.\left(\frac{1}{4}-\frac{1}{300}\right)\)
\(\Rightarrow A=\frac{37}{60}\)
Bạn ơi cho mình hỏi \(\frac{1}{2}\)ở đâu có vậy