Cho S = -\(\frac{4}{1}\). \(\frac{4}{5}\)-\(\frac{4}{5}\). \(\frac{4}{9}\)-\(\frac{4}{9}\).\(\frac{4}{13}\)-....- \(\frac{4}{2013}\).\(\frac{4}{2017}\)
Tính 2017S
Cho S = \(-\frac{4}{1}.\frac{4}{5}-\frac{4}{5}.\frac{4}{9}-\frac{4}{9}.\frac{4}{13}-...-\frac{4}{2013}.\frac{4}{2017}\) Vậy, 2017S bằng bao nhiêu ?
S=-4/1.4/5-4/5.4/9-4/9.4/13-...-4/2013.4/2017
=-4^2/1.5-4^2/5.9-4^2/9.13-...-4^2/2013.2017
=-4(4/1.5+4/5.9-4/9.13-...-4/2013.2017)
=-4(1-1/5+1/5-1/9+1/9-1/13-...-1/2013-1/2017)
=-4(1-1/2017)
=-4.2016/2017=-8064/2017
Cho S = \(-\frac{4}{1}.\frac{4}{5}-\frac{4}{5}.\frac{4}{9}-.......-\frac{4}{2013}.\frac{4}{2017}\)
Hỏi 2017S = ........
MN trình bày giùm mình nha Arigato ( cúi đầu)
Ta có : S= - 4/1 .4/5 - 4/5 .4/9-...- 4/2013 .4/2017
= -4 .( 4/1.5+4/5.9+...+4/2013.2017 )
= -4 . (1-1/5+1/5-1/9+...+1/2013-1/2017 )
= -4 . (1-1/2017)
= -4 .2016/2017
= -8064/2017
=> 2017S= -8064/2017 .2017 = -8064
Tính \(S=-\frac{4}{1}.\frac{4}{5}-\frac{4}{5}.\frac{4}{9}-\frac{4}{9}-\frac{4}{13}-...-\frac{4}{2013}.\frac{4}{2017}\)
Cho S=\(-\frac{4}{1}\).\(\frac{4}{5}\)\(-\frac{4}{5}\).\(\frac{4}{9}\)\(-\frac{4}{9}\).\(\frac{4}{13}\)\(-\)....\(-\frac{4}{2013}\).\(\frac{4}{2017}\)
Vậy 2017S=...........
Tính S = \(\frac{-4}{1}\). \(\frac{4}{5}\)- \(\frac{4}{5}\). \(\frac{4}{9}\)- \(\frac{4}{9}\). \(\frac{4}{13}\) -...- \(\frac{4}{2013}\). \(\frac{4}{2017}\)
\(\left(-1\frac{1}{6}\right)\left(\frac{1-\frac{3}{5}+\frac{3}{11}-\frac{3}{13}}{\frac{1}{3}-\frac{1}{5}+\frac{1}{11}-\frac{1}{13}}\right):\left(\frac{4-\frac{4}{17}+\frac{4}{19}-\frac{4}{2013}}{5-\frac{5}{17}+\frac{5}{19}-\frac{5}{2013}}\right)\)
tính
\(\left(-1\frac{1}{6}\right)\left(\frac{1-\frac{3}{5}+\frac{3}{11}-\frac{3}{13}}{\frac{1}{3}-\frac{1}{5}+\frac{1}{11}-\frac{1}{13}}\right)\left(\frac{4-\frac{4}{17}+\frac{4}{19}-\frac{4}{2013}}{5-\frac{5}{7}+\frac{5}{19}-\frac{5}{2013}}\right)\)
\(=-\frac{7}{6}.\left(\frac{3\left(\frac{1}{3}-\frac{1}{5}+\frac{1}{11}-\frac{1}{13}\right)}{\frac{1}{3}-\frac{1}{5}+\frac{1}{11}-\frac{1}{13}}\right):\left(\frac{4.\left(1-\frac{1}{7}+\frac{1}{19}-\frac{1}{2013}\right)}{5.\left(1-\frac{1}{7}+\frac{1}{19}-\frac{1}{2013}\right)}\right)\)
\(=-\frac{7}{6}.3:\frac{4}{5}=-\frac{7}{2}.\frac{5}{4}=-\frac{35}{8}\)
Rút gọn
1. \(\frac{5}{9}.\frac{7}{13}+\frac{5}{9}.\frac{9}{13}-\frac{5}{9}.\frac{3}{13}\)
2. \(\left(\frac{1+\frac{1}{5}+\frac{1}{7}+\frac{1}{11}}{2+\frac{2}{5}+\frac{2}{7}+\frac{2}{17}}:\frac{4-\frac{4}{7}+\frac{4}{9}-\frac{4}{13}}{1-\frac{1}{7}+\frac{1}{9}-\frac{1}{13}}\right):\frac{838383}{808080}\)
1. \(\frac{5}{9}.\frac{7}{13}+\frac{5}{9}.\frac{9}{13}-\frac{5}{9}.\frac{3}{13}\)
= \(\frac{5}{9}\) .(\(\frac{7}{13}+\frac{9}{13}-\frac{3}{13}\) )
= \(\frac{5}{9}\) . 1 = \(\frac{5}{9}\)
Tính nhanh:
\(\frac{\frac{1}{9}-\frac{1}{7}-\frac{1}{11}}{\frac{4}{9}-\frac{4}{7}-\frac{4}{11}}+\frac{\frac{3}{5}-\frac{3}{25}-\frac{3}{125}-\frac{3}{625}}{\frac{4}{5}-\frac{4}{25}-\frac{4}{125}-\frac{4}{625}}\)
Ai làm nhanh, chi tiết thì mk tick cho!!!
\(\frac{\frac{1}{9}-\frac{1}{7}-\frac{1}{11}}{\frac{4}{9}-\frac{4}{7}-\frac{4}{11}}+\frac{\frac{3}{5}-\frac{3}{25}-\frac{3}{125}-\frac{3}{625}}{\frac{4}{5}-\frac{4}{25}-\frac{4}{125}-\frac{4}{625}}\)
\(=\frac{1\left(\frac{1}{9}-\frac{1}{7}-\frac{1}{11}\right)}{4.\left(\frac{1}{9}-\frac{1}{7}-\frac{1}{11}\right)}+\frac{3.\left(\frac{1}{5}-\frac{1}{25}-\frac{1}{125}-\frac{1}{625}\right)}{4.\left(\frac{1}{5}-\frac{1}{25}-\frac{1}{125}-\frac{1}{625}\right)}\)
\(=\frac{1}{4}+\frac{3}{4}=1\)
\(\frac{\frac{1}{9}-\frac{1}{7}-\frac{1}{11}}{\frac{4}{9}-\frac{4}{7}-\frac{4}{11}}+\frac{\frac{3}{5}-\frac{3}{25}-\frac{3}{125}-\frac{3}{625}}{\frac{4}{5}-\frac{4}{25}-\frac{4}{125}-\frac{4}{625}}\)
\(=\frac{\frac{1}{9}-\frac{1}{7}-\frac{1}{11}}{4\left(\frac{1}{9}-\frac{1}{7}-\frac{1}{11}\right)}+\frac{3\left(\frac{1}{5}-\frac{1}{25}-\frac{1}{125}-\frac{1}{625}\right)}{4\left(\frac{1}{5}-\frac{1}{25}-\frac{1}{125}-\frac{1}{625}\right)}\)
\(=\frac{1}{4}+\frac{3}{4}\)
=1
Ta có:
\(\frac{\frac{1}{9}-\frac{1}{7}-\frac{1}{11}}{\frac{4}{9}-\frac{4}{7}-\frac{4}{11}}=\frac{\frac{1}{9}-\frac{1}{7}-\frac{1}{11}}{4\left[\frac{1}{9}-\frac{1}{7}-\frac{1}{11}\right]}=\frac{1}{4}\)
Lại có:
\(\frac{\frac{3}{5}-\frac{3}{25}-\frac{3}{125}-\frac{3}{625}}{\frac{4}{5}-\frac{4}{25}-\frac{4}{125}-\frac{4}{625}}=\frac{3\left[\frac{1}{5}-\frac{1}{25}-\frac{1}{125}-\frac{1}{625}\right]}{4\left[\frac{1}{5}-\frac{1}{25}-\frac{1}{125}-\frac{1}{625}\right]}=\frac{3}{4}\)
Vậy:
\(\frac{\frac{1}{9}-\frac{1}{7}-\frac{1}{11}}{\frac{4}{9}-\frac{4}{7}-\frac{4}{11}}+\frac{\frac{3}{5}-\frac{3}{25}-\frac{3}{125}-\frac{3}{625}}{\frac{4}{5}-\frac{4}{25}-\frac{4}{125}-\frac{4}{625}}=\frac{1}{4}+\frac{3}{4}=1\)
1. Tính:
a. \(75\%-1\frac{1}{2}.\frac{4}{3}+1,5:\frac{-9}{4}-\left(-\frac{1}{2}\right)^2\)
b. \(\frac{-4}{9}.\frac{6}{13}+7\frac{4}{9}-\frac{4}{9}:\frac{13}{7}-5\frac{4}{9}-2\)
2. Tìm x, biết:
a. \(x\in Z,-1\le\frac{x}{5}< 0\)
*làm nhanh nha, mk cần gấp lắm