Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(1\dfrac{1}{2}x1\dfrac{1}{3}x1\dfrac{1}{4}x1\dfrac{1}{5}x1\dfrac{1}{6}x1\dfrac{1}{7}x1\dfrac{1}{8}x1\dfrac{1}{9}\)
\(=\dfrac{3}{2}x\dfrac{4}{3}x\dfrac{5}{4}x\dfrac{6}{5}x\dfrac{7}{6}x\dfrac{8}{7}x\dfrac{9}{8}x\dfrac{10}{9}\)
\(=x^7.\dfrac{3.4.5.6.7.8.9.10}{2.3.4.5.6.7.8.9}\)
\(=x^7.\dfrac{10}{2}\)
\(=5x^7\)
\(=\dfrac{3}{2}\times\dfrac{4}{3}\times\dfrac{5}{4}\times...\times\dfrac{9}{8}\times\dfrac{10}{9}=\dfrac{10}{2}=5\)
\(...=\dfrac{3}{2}x\dfrac{4}{3}x\dfrac{5}{4}x\dfrac{6}{5}x\dfrac{7}{6}....x\dfrac{1000}{999}\)
\(=\dfrac{1}{2}x\dfrac{1000}{1}=500\)
=3/2x4/3x5/4x....x1000/999
=1/2x1000=500
mình chưa chắc là đúng đâu nhé
` a/`
` 2 - 1 5/6 + 2 2/3 = 2 - 11/6 - 8/3 = 1/6+ 8/3 = 1/6 + 16/6 = 17/6 `
`b/`
`5/9 xx ( 2 5/6 - 1 2/3 ) = 5/9 xx ( 17/6 - 5/3 ) = 5/9 xx 7/6 = 35/54 `
`c/`
` 1 1/3 : ( 2 + 1 1/6 : 2 5/6 ) `
`= 4/3 : ( 2 + 7/6 : 17/6 ) `
`= 4/3 : ( 2 + 7/6 xx 6/17 )`
`= 4/3 : ( 2 + 7/17 ) `
`= 4/3 : ( 34/17 + 7/17 ) `
`= 4/3 : 41/17 `
`= 4/3 xx 17/41 `
`= 68/123`
` d/`
` 2 3/5 : 3/4 xx 1 4/5 = 13/5 xx 4/3 xx 9/5 =52/15 xx 9/5 = 156/25`
a: \(1\dfrac{1}{2}\cdot1\dfrac{1}{3}\cdot1\dfrac{1}{4}\)
\(=\dfrac{3}{2}\cdot\dfrac{4}{3}\cdot\dfrac{5}{4}\)
\(=\dfrac{5}{2}\)
b: \(1\dfrac{1}{2}:1\dfrac{1}{3}:1\dfrac{1}{4}\)
\(=\dfrac{3}{2}:\dfrac{4}{3}:\dfrac{5}{4}\)
\(=\dfrac{3}{2}\cdot\dfrac{3}{4}\cdot\dfrac{4}{5}=\dfrac{9}{10}\)
\(\dfrac{4}{9}+\dfrac{5}{8}\)=\(\dfrac{32}{72}+\dfrac{45}{72}=\dfrac{77}{72}\)
\(\dfrac{6}{10}+\dfrac{9}{2}=\dfrac{6}{10}+\dfrac{45}{10}=\dfrac{51}{10}\)
\(\dfrac{10}{2}-\dfrac{5}{2}=\dfrac{5}{2}\)
\(\dfrac{8}{8}x1=\dfrac{8}{8}x\dfrac{1}{1}=\dfrac{8}{8}\)
= 13/5 x 1/4 x 3/2
= 13 x 1 x 3/ 5 x 4 x 2
= 39/40
\(1\dfrac{1}{3}\times1\dfrac{1}{8}\times1\dfrac{1}{15}\times1\dfrac{1}{24}\times1\dfrac{1}{35}\)
= \(\dfrac{4}{3}\times\dfrac{9}{8}\times\dfrac{16}{15}\times\dfrac{25}{24}\times\dfrac{36}{35}\)
= \(\dfrac{4\times9\times16\times25\times36}{3\times8\times15\times24\times35}\)
= \(\dfrac{1\times2\times2\times25\times36}{1\times2\times15\times24\times35}\)
= \(\dfrac{4\times25\times36}{30\times24\times35}\)
= \(\dfrac{1\times25\times36}{30\times6\times35}=\dfrac{1}{7}\)
Sai rồi nhé! Từ dấu bằng thứ 2 xuống dấu bằng thứ 3 bạn làm sao đc z?
\(=\dfrac{4}{5}+\dfrac{2}{3}x.\dfrac{55}{4}=\dfrac{4}{5}+\dfrac{55}{6}x\)
đề này bị lỗi đáng lẽ :
C = \(\dfrac{2011\times2010-1}{2012\times2010-2011}\) +1\(\dfrac{2}{3}\) x 1\(\dfrac{2}{5}\)x1\(\dfrac{2}{7}\)x1\(\dfrac{2}{9}\)-\(\dfrac{11}{3}\)
C = \(\dfrac{(2012-1)\times2010-1}{2012\times2010-2011}\) + \(\dfrac{5}{3}\)x\(\dfrac{7}{5}\)x\(\dfrac{9}{7}\)x\(\dfrac{11}{9}\) - \(\dfrac{11}{3}\)
C = \(\dfrac{2012\times2010-2010-1}{2012\times2010-2011}\) + \(\dfrac{11}{3}\) - \(\dfrac{11}{3}\)
C = \(\dfrac{2012\times2010-2011}{2012\times2010-2011}\) + 0
C = 1
Ta có:
\(C=\dfrac{2011\times2010-1}{2012\times2010+2011}+1\dfrac{2}{3}\times1\dfrac{2}{5}\times1\dfrac{2}{7}\times1\dfrac{2}{9}-\dfrac{11}{3}\\ =\dfrac{2011\times\left(2011-1\right)-1}{\left(2011+1\right)\left(2011-1\right)+2011}+\dfrac{5}{3}\times\dfrac{7}{5}\times\dfrac{9}{7}\times\dfrac{11}{9}-\dfrac{11}{3}\\ =\dfrac{2011\times2011-2011-1}{2011\times2011-1+2011}+\dfrac{11}{3}-\dfrac{11}{3}\\ =\dfrac{2011\times2011-2012}{2011\times2011+2010}\)
Đs....