tìm trong câu hỏi tương tự bạn nhé, h họ đi ngủ rồi
xin lỗi đã làm phiền !
\(B=\left(1+\frac{1}{2}\right).\left(1+\frac{1}{5}\right).\left(1+\frac{1}{9}\right).....\left(1+\frac{1}{740}\right)\)
\(B=\left(\frac{3}{2}\right).\left(\frac{6}{5}\right).\left(\frac{10}{9}\right).....\left(\frac{741}{740}\right)\)
\(B=\left(\frac{3.2}{2.2}\right).\left(\frac{6.2}{5.2}\right).\left(\frac{10.2}{9.2}\right).....\left(\frac{741.2}{740.2}\right)\)
\(B=\left(\frac{2.3}{1.4}\right).\left(\frac{3.4}{2.5}\right).\left(\frac{4.5}{3.6}\right).....\left(\frac{38.39}{37.40}\right)\)
\(B=\frac{2.3.4.5.....38}{1.2.3.4.....37}.\frac{3.4.5.....39}{4.5.6.....40}\)
\(B=\frac{38}{1}.\frac{3}{40}=\frac{57}{20}\)
CHÚC EM HỌC TÔT
