Question

Bài 1 : Tính : A = \(\left(1-\frac{1}{8}\right).\left(1-\frac{1}{9}\right).\left(1-\frac{1}{10}\right)...\left(1-\frac{1}{100}\right)\)( Trình bày rõ => like ) 

Answer 1

\(A=\left(1-\frac{1}{8}\right)\times\left(1-\frac{1}{9}\right)\times\left(1-\frac{1}{10}\right)\times...\times\left(1-\frac{1}{100}\right)\)

\(A=\frac{7}{8}\times\frac{8}{9}\times\frac{9}{10}\times...\times\frac{98}{99}\times\frac{99}{100}\)

\(A=\frac{7\times8\times9\times...\times98\times99}{8\times9\times10\times...\times99\times100}=\frac{7}{100}\)

Answer 2

=>A=7/8*8/9*9/10*...*99/100

=>A=(7*8*9*...*99)/(8*9*10*...*100)=7/100

Vậy A=.............

Answer 3

\(A=\frac{7}{8}.\frac{8}{9}.\frac{9}{10}.....\frac{99}{100}\)

\(A=\frac{7.8.9.....99}{8.9.10.....100}\)

\(A=\frac{7}{100}\)

Answer 4

 \(\frac{7}{8}\times\frac{8}{9}\times\frac{9}{10}...\times\frac{99}{100}\)

<=> \(\frac{7}{1}\times\frac{1}{1}\times\frac{1}{1}...\times\frac{1}{100}\)

=> 7/100

Đs: 7/100