Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Bài 2:
\(B=\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right).\left(1-\frac{1}{4}\right).......\left(1-\frac{1}{2004}\right)\)
\(=\frac{1}{2}.\frac{2}{3}.\frac{3}{4}....\frac{2003}{2004}\)
\(=\frac{1}{2004}\)
\(=\frac{3}{2}\cdot\frac{4}{3}\cdot.....\cdot\frac{2014}{2013}\)
\(=\frac{2}{2013}\)
\(1\frac{1}{3}.1\frac{1}{8}.1\frac{1}{15}...1\frac{1}{120}\)
\(=\frac{4}{3}.\frac{9}{8}.\frac{16}{15}...\frac{121}{120}\)
\(=\frac{2.2}{1.3}.\frac{3.3}{2.4}.\frac{4.4}{3.5}...\frac{11.11}{10.12}\)
\(=\frac{2.3.4...11}{1.2.3...10}.\frac{2.3.4...11}{3.4.5...12}\)
\(=11.\frac{2}{12}=11.\frac{1}{6}=\frac{11}{6}\)
\(A=\frac{1}{2}x\frac{2}{3}x\frac{3}{4}x...x\frac{2006}{2007}=\frac{1}{2007}\)
k nha bạn
\(\frac{3}{4}x\frac{8}{9}x...x\frac{120}{121}=\frac{1x3}{2x2}x\frac{2x4}{3x3}x...x\frac{10x12}{11x11}=\frac{1x3x2x4x...x10x12}{2x2x3x3x...x11x11}\)
\(\frac{\left(1x2x3x4x...x10\right)x\left(3x4x5x6x...x12\right)}{\left(2x3x4x5x...x11\right)x\left(2x3x4x5x...x11\right)}=\frac{12}{11x2}=\frac{6}{11}\)