Question

5/2x4+5/4x6+5/6x8+.....+5/48x60

Answer 1

\(\frac{5}{2\cdot4}+\frac{5}{4\cdot6}+\frac{5}{6\cdot8}+.....+\frac{5}{48\cdot60}\)

\(=\frac{5}{2}\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+.....+\frac{1}{48}-\frac{1}{50}\right)\)

\(=\frac{5}{2}\left(\frac{1}{2}-\frac{1}{50}\right)\)

Tự tính nốt :p