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11 tháng 4 2017

dat off roi

11 tháng 4 2017

3/4x8/9x15/16x24/25x35/36=7/12

11 tháng 4 2017

on lai roi

11 tháng 4 2017

ai và kết bạn với mình thì mình cho 3

11 tháng 4 2017

\(\left(1-\frac{1}{4}\right)x\left(1-\frac{1}{9}\right)x\left(1-\frac{1}{16}\right)x\left(1-\frac{1}{25}\right)x\left(1-\frac{1}{36}\right)\)

\(=\)\(\frac{3}{4}\) x       \(\frac{8}{9}\)    x       \(\frac{15}{16}\)   x       \(\frac{24}{25}\)   x       \(\frac{35}{36}\)

\(=\frac{7}{12}\)

( 1 - 1/4 ) x ( 1 -1/9 ) x ( 1 - 1/16 ) x ( 1 - 1/25 ) x ( 1/ 36)

= ( 4/4 - 1/4 ) x ( 9/9- 1/9 ) x ( 16/16 - 1/16 ) x ( 25/25 - 1/25 ) x ( 36/36 - 1/36) 

= 3/4 x 8/9 x 15/16 x 24/25 x 35/36 

= ( 3/4 x 8/9 ) x 15/16 x ( 24/25 x 35/36 ) 

= 2/3 x 15/16 x 14/15

= 2/3 x 7/8

= 7/12

tk và kb giúp mk nha!!!!!!!

11 tháng 4 2017

bận nên ko viết lại đề bài !!!!!!!!!!!!!!

=\(\frac{3}{4}.\frac{8}{9}.\frac{15}{16}.\frac{24}{25}.\frac{35}{36}\)

=\(\frac{1.2.3.2.35}{1.3.16.5.3}\)

=\(\frac{7}{4.3}\)

=\(\frac{7}{12}\)

nhớ k cho milk nha !!!!! :p :p

\(\left(1-\frac{1}{4}\right)x\left(1-\frac{1}{9}\right)x\left(1-\frac{1}{16}\right)\)\(x\left(1-25\right)x\left(1-\frac{1}{36}\right)\)

\(\left(\frac{4}{4}-\frac{1}{4}\right)x\left(\frac{9}{9}-\frac{1}{9}\right)x\left(\frac{16}{16}-\frac{1}{16}\right)\)\(x\left(\frac{25}{25}-\frac{1}{25}\right)x\left(\frac{36}{36}-\frac{1}{36}\right)\)

=\(\frac{3}{4}x\frac{8}{9}x\frac{15}{16}x\frac{24}{25}x\frac{35}{36}\)

=\(\left(\frac{3}{4}x\frac{8}{9}\right)x\left(\frac{24}{25}x\frac{35}{36}\right)x\frac{15}{16}\)

=\(\frac{1.2}{1.3}x\frac{6.7}{5.9}x\frac{15}{16}\)

=\(\frac{2}{3}x\frac{42}{45}x\frac{15}{16}=\frac{2}{3}x\frac{14}{15}x\frac{15}{16}\) 

\(\frac{2}{3}x\frac{7}{1}x\frac{1}{8}=\frac{2}{3}x\frac{7}{8}=\frac{1}{3}x\frac{7}{4}=\frac{7}{12}\)

xong rùi đó tk ủng  hộ mk nha!!!!!!!!!!!

27 tháng 7 2017

(1-1/2)×(1-1/3)×(1-1/4)×...×(1-1/9)

11 tháng 4 2017

giải giúp mk vs

11 tháng 4 2017

\(\left(1-\frac{1}{4}\right).\left(1-\frac{1}{9}\right).\left(1-\frac{1}{16}\right).\left(1-\frac{1}{25}\right).\left(1-\frac{1}{36}\right)\)

\(=\frac{3}{4}.\frac{8}{9}.\frac{15}{16}.\frac{24}{25}.\frac{35}{36}=\frac{3.8.15.24.35}{4.9.16.25.36}=\frac{1.3.2.4.3.5.4.6.5.7}{2.2.3.3.4.4.5.5.6.6}\)

\(=\frac{\left(1.2.3.4.5\right).\left(3.4.5.6.7\right)}{\left(2.3.4.5.6\right).\left(2.3.4.5.6\right)}=\frac{1.7}{2.2}=\frac{7}{4}\)

22 tháng 6 2017

lời giải luôn nhé

16 tháng 10 2021

\(\left(1-\frac{1}{4}\right)\times\left(1-\frac{1}{9}\right)\times\left(1-\frac{1}{16}\right)\times\left(1-\frac{1}{25}\right)\times\left(1-\frac{1}{36}\right)\)

\(=\)\(\frac{3}{4}\times\frac{8}{9}\times\frac{15}{16}\times\frac{24}{25}\times\frac{35}{36}\)

\(=\)\(\frac{3\times8\times15\times24\times35}{4\times9\times16\times25\times36}\)

\(=\)\(\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\frac{\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}3\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\times4\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\times2\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\times5\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\times3\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\times6\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\times4\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\times5\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\times7}{4\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\times3\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\times3\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\times8\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\times2\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\times5\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\times5\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\times6\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\text{​​}\times6}\)

\(=\)\(\frac{7\text{​​}\text{​​}\text{​​}\times4}{8\times6}\)

\(=\)\(\frac{7\times4}{4\times2\times6}\)

\(=\)\(\frac{7}{2\times6}\)

\(=\)\(\frac{7}{12}\)

19 tháng 6 2016

\(K=\left(1-\frac{1}{4}\right)x\left(1-\frac{1}{9}\right)x\left(1-\frac{1}{16}\right)x\left(1-\frac{1}{25}\right)x\left(1-\frac{1}{36}\right)\)

\(K=\frac{3}{4}x\frac{8}{9}x\frac{15}{16}x\frac{24}{25}x\frac{35}{36}\)

tự rút gọn

19 tháng 6 2016

thôi tui làm nốt cho

...

\(K=\frac{1x3}{2x2}x\frac{2x4}{3x3}x\frac{3x5}{4x4}x\frac{4x6}{5x5}x\frac{5x7}{6x6}\)

\(K=\frac{7}{2}\)

21 tháng 7 2016

\(\left(1-\frac{1}{4}\right)x\left(1-\frac{1}{9}\right)x\left(1-\frac{1}{16}\right)x\left(1-\frac{1}{25}\right)=\frac{3}{4}x\frac{8}{9}x\frac{15}{16}x\frac{24}{25}\)

\(=\frac{3x8x15x24}{4x9x16x25}\)

\(=\frac{3x2x4x3x5x4x2x3}{2x2x3x3x4x4x5x5}\)(chỗ này rút gọn đi)

\(=\frac{3}{5}\)

28 tháng 7 2017

đáp số cuối cùng là 0 vì 1-1/4 = 0/4 = 0 x cho những số nào khác cũng bằng 0 thôi

28 tháng 7 2017

\(\left(1-\frac{1}{4}\right)\times\left(1-\frac{1}{9}\right)\times\left(1-\frac{1}{16}\right)\times...\times\left(1-\frac{1}{10000}\right)\)

\(=\frac{3}{4}\times\frac{8}{9}\times\frac{15}{16}\times...\times\frac{999}{10000}\)

\(=\frac{1\times3}{2\times2}\times\frac{2\times4}{3\times3}\times\frac{3\times5}{4\times4}\times...\times\frac{99\times101}{100\times100}\)

\(=\frac{1}{2}\times\frac{101}{100}\)

\(=\frac{101}{200}\)

29 tháng 7 2020

\(B=\frac{10}{18}\times\frac{22}{30}\times\frac{36}{44}\times...\times\frac{200}{209}=\frac{1\times10}{2\times9}\times\frac{2\times11}{3\times10}\times\frac{3\times12}{4\times11}\times...\times\frac{10\times20}{11\times19}\)

\(=\frac{1\times10\times2\times11\times3\times12\times...\times10\times20}{2\times9\times3\times10\times4\times11\times...\times11\times19}=\frac{\left(1\times2\times3\times...\times10\right)\times\left(10\times11\times12\times...\times20\right)}{\left(2\times3\times4\times...\times11\right)\times\left(9\times10\times11\times...\times19\right)}\)

\(=\frac{1\times20}{11\times9}=\frac{20}{99}\)

Sửa đề \(C=\left(1-\frac{1}{4}\right)\times\left(1-\frac{1}{9}\right)\times\left(1-\frac{1}{16}\right)\times...\times\left(1-\frac{1}{100}\right)\)

\(=\frac{3}{4}\times\frac{8}{9}\times\frac{15}{16}\times...\times\frac{99}{100}=\frac{3\times8\times15\times...\times99}{4\times9\times16\times...\times100}=\frac{1\times3\times2\times4\times3\times5\times...\times9\times11}{2\times2\times3\times3\times4\times4\times...\times10\times10}\)

\(=\frac{\left(1\times2\times3\times....\times9\right)\times\left(3\times4\times5\times...\times11\right)}{\left(2\times3\times4\times...\times10\right)\times\left(2\times3\times4\times...\times10\right)}=\frac{1\times11}{10\times2}=\frac{11}{20}\)

29 tháng 7 2020

b) C=(1- 1/4) x (1- 1/9) x (1-1/16) x (1- 1/100)

C = 3/4 . 8/9 . 15/16.......99/100

C= 3.8.15....99/4.9.16...100

C= 1.3.2.4.3.5....9.11/ 2.2.3.3.4.4......10.10

C= 1.2.3.4...9/ 2.3.4.5....10 . 3.4.5....11/ 2.3.4.5...10

C= 1/10 . 11/2

C= 11/20

Mk nghĩ đề nt mới đúng 

29 tháng 1 2024

\(A=\left(1-\dfrac{1}{4}\right)\left(1-\dfrac{1}{9}\right)\cdot...\cdot\left(1-\dfrac{1}{9801}\right)\)

\(=\left(1-\dfrac{1}{2}\right)\left(1+\dfrac{1}{2}\right)\left(1-\dfrac{1}{3}\right)\left(1+\dfrac{1}{3}\right)\cdot...\left(1-\dfrac{1}{99}\right)\left(1+\dfrac{1}{99}\right)\)

\(=\left(\dfrac{1}{2}\cdot\dfrac{2}{3}\cdot...\cdot\dfrac{98}{99}\right)\cdot\left(\dfrac{3}{2}\cdot\dfrac{4}{3}\cdot...\cdot\dfrac{100}{99}\right)\)

\(=\dfrac{1}{99}\cdot\dfrac{100}{2}=\dfrac{50}{99}\)