Cho A=\(\frac{1}{3}.\frac{4}{6}.\frac{7}{9}.\frac{10}{12}...\frac{208}{210}\)

Chứng minh A<\(\frac{1}{25}\)

  Cho A=\(\frac{1}{3}.\frac{4}{6}\frac{7}{9}.\frac{10}{12}...\frac{208}{210}\)

   CMR: \(\frac{1}{52}

Cho A=\(\frac{1}{3}x\frac{4}{6}x\frac{7}{9}x.....x\frac{208}{210}\)

  Chứng minh :A<\(\frac{1}{25}\)

cho A=\(\frac{1}{3}.\frac{4}{6}.\frac{7}{9}.\frac{10}{12}.....\frac{208}{210}\)

cmr: A<\(\frac{1}{25}\)

giúp mik với mik cần gấp

Cho A=\(\frac{1}{3}.\frac{4}{6}.\frac{7}{9}...\frac{208}{210},CMR:A< \frac{1}{25}\)

Cho biểu thức A= \(\frac{2}{1}\times\frac{4}{3}\times\frac{6}{5}\times\frac{8}{7}\times\frac{10}{9}\times...\times\frac{100}{99}\)Chứng minh rằng 12<A<13

Chứng minh:

\(\frac{1}{3}\). \(\frac{4}{6}\). \(\frac{7}{9}\).....\(\frac{208}{210}\)< \(\frac{1}{25}\). 

Chứng minh rằng: Nếu \(\frac{a}{b}=\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+\frac{1}{6}+\frac{1}{7}+\frac{1}{8}+\frac{1}{9}+\frac{1}{10}​\)

Thì a chia hết cho 13

Bài 1 : Cho A = \(\frac{1}{2}.\frac{3}{4}.\frac{5}{6}.\frac{7}{8}...\frac{79}{80}\)

Chứng minh rằng A < \(\frac{1}{9}\)

Bài 4 : Chứng minh rằng:  1.3.5.7....19 = \(\frac{11}{2}.\frac{12}{2}.\frac{13}{2}...\frac{20}{2}\)