\(\frac{4}{3}\times\frac{9}{8}\times...\times\frac{81}{80}=\frac{2^2}{1\times3}\times\frac{3^2}{2\times4}\times...\times\frac{9^2}{8\times10}\)

\(=\frac{2\times3\times4\times...\times9}{1\times2\times3\times...\times8}\times\frac{2\times3\times4\times...\times9}{3\times4\times5\times...\times10}\\ =\frac{9}{1}\times\frac{2}{10}=\frac{9}{5}\)

4/3.9/8.16/15.25/24.36/35.49/48.64/63.81/80

=3/2.16/15.25/24.36/35.49/48.64/63.81/80

=5/3.36/35.49/48.64/63.81/80

=7/4.64/63.81/80

=9/5

+

=(1-1/2)(1+1/2)*...*(1+1/10)(1-1/10)

=1/2*2/3*...*9/10*3/2*4/3*...*11/10

=1/10*11/2

=11/20

Dấu chấm là gì vậy bạn

Bạn ơi dấu chấm là gì để mình làm tiếp!

Dấu chấm "." còn đc gọi là dấu nhân "x"

a,\(\frac{4}{3}\)x \(\frac{9}{8}\)x \(\frac{16}{15}\)x \(\frac{25}{24}\)

= \(\frac{5}{3}\)

b, \(\frac{4}{3}\)x \(\frac{9}{8}\)x \(\frac{16}{15}\)x \(\frac{25}{24}\)x \(\frac{36}{35}\)x \(\frac{49}{48}\)x \(\frac{64}{63}\)x \(\frac{81}{80}\)

= \(\frac{9}{5}\)

chi tiết hơn đc k bn

chi tiết hơn đi bạn

=(3.8.15.24.36.48.63)/(4.9.16.25.36.49.64)=81/140