\(1\frac{1}{3}.1\frac{1}{8}.1\frac{1}{15}.1\frac{1}{24}...1\frac{1}{99}\)
\(=\frac{4}{3}.\frac{9}{8}.\frac{16}{15}.\frac{25}{24}....\frac{100}{99}\)
\(=\frac{2.2}{1.3}.\frac{3.3}{2.4}.\frac{4.4}{3.5}.\frac{5.5}{4.6}...\frac{10.10}{9.11}\)
\(=\frac{2.2.3.3.4.4.5.5....10.10}{1.3.2.4.3.5.4.6....9.11}\)
\(=\frac{\left(2.3.4.5....10\right)\left(2.3.4.5...10\right)}{\left(1.2.3.4.5...9\right)\left(3.4.5.6...11\right)}\)
\(=\frac{10.2}{11}\)
\(=\frac{20}{11}\)
Có gì không hiểu cứ hỏi nhé. Học tốt <3
Tks bn nha!