tinh nhanh
\(\left(1-\dfrac{28}{10}\right).\left(1-\dfrac{52}{22}\right).\left(1-\dfrac{80}{36}\right)....\left(1-\dfrac{21808}{10900}\right)\)
Những câu hỏi liên quan
Tính
P=\(\left(1-\dfrac{28}{10}\right)\left(1-\dfrac{52}{22}\right)\left(1-\dfrac{80}{36}\right)...\left(1-\dfrac{21808}{10900}\right)\)
Q=\(\dfrac{1+\dfrac{1}{2}+\dfrac{1}{3}+...+\dfrac{1}{2012}}{\dfrac{2013}{1}+\dfrac{2014}{2}+\dfrac{2015}{3}+...+\dfrac{4023}{2011}+\dfrac{4024}{2012}-2012}\)
2.Tính:
Aleft(dfrac{1}{10}-1right).left(dfrac{1}{11}-1right)left(dfrac{1}{12}-1right).....left(dfrac{1}{100}-1right)
Bleft(1-dfrac{1}{2^2}right)left(1-dfrac{1}{3^2}right)left(1-dfrac{1}{10^2}right)
Cleft(dfrac{7}{9}+1right)left(dfrac{7}{20}+1right)left(dfrac{7}{33}+1right)...left(dfrac{7}{108080}+1right)
Dleft(1-dfrac{28}{10}right)left(1-dfrac{52}{22}right)left(1-dfrac{80}{36}right)...left(1-dfrac{21808}{10900}right)
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2.Tính:
A=\(\left(\dfrac{1}{10}-1\right).\left(\dfrac{1}{11}-1\right)\left(\dfrac{1}{12}-1\right).....\left(\dfrac{1}{100}-1\right)\)
B=\(\left(1-\dfrac{1}{2^2}\right)\left(1-\dfrac{1}{3^2}\right)\left(1-\dfrac{1}{10^2}\right)\)
C=\(\left(\dfrac{7}{9}+1\right)\left(\dfrac{7}{20}+1\right)\left(\dfrac{7}{33}+1\right)...\left(\dfrac{7}{108080}+1\right)\)
D=\(\left(1-\dfrac{28}{10}\right)\left(1-\dfrac{52}{22}\right)\left(1-\dfrac{80}{36}\right)...\left(1-\dfrac{21808}{10900}\right)\)
Tính nhanh:
D=\(\left(1-\frac{28}{10}\right)\left(1-\frac{52}{22}\right)\left(1-\frac{80}{36}\right).....\left(1-\frac{21808}{10900}\right)\)
D=18/10.30/22...........10908/10900
D=18.30........10908 / 10.22.10900
D=(2.9)(3.10).....(101.108) / (1.10)(2.11).....(100.109)
D=(2.3.......101)(9.10......108) / (1.2....100) (10.11....109)
D=101.9/109=909/109
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Tính nhanh: \(M=\left(\frac{28}{10}-1\right).\left(\frac{52}{22}-1\right).\left(\frac{80}{36}-1\right)...\left(\frac{21808}{10900}-1\right)\)
Làm ơn giúp mình với!Mình đang cần gấp.Bạn nào trả lời được mình sẽ TICK và KẾT BẠN (làm ơn có lời giải nha)
tinh nhanh\(\left(1-\dfrac{1}{21}\right).\left(1-\dfrac{1}{28}\right)....\left(1-\dfrac{1}{1326}\right)\)
\(\left(1-\dfrac{1}{21}\right)\left(1-\dfrac{1}{28}\right)...\left(1-\dfrac{1}{1326}\right)\)
\(=\left(1-\dfrac{2}{42}\right)\left(1-\dfrac{2}{56}\right)\left(1-\dfrac{2}{72}\right)...\left(1-\dfrac{2}{2652}\right)\)
\(=\dfrac{40}{42}.\dfrac{54}{56}.\dfrac{70}{72}...\dfrac{2650}{2652}\)
\(=\dfrac{5.8}{6.7}.\dfrac{6.9}{7.8}.\dfrac{7.10}{8.9}...\dfrac{50.53}{51.52}\)
\(=\dfrac{5.6.7...50}{6.7.8...51}.\dfrac{8.9.10...53}{7.8.9...52}\)
\(=\dfrac{5}{51}.\dfrac{53}{7}=\dfrac{265}{357}\)
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Tính
Aleft(dfrac{1}{3}-1right)left(dfrac{1}{6}-1right)left(dfrac{1}{10}-1right)left(dfrac{1}{15}-1right)left(dfrac{1}{21}-1right)left(dfrac{1}{28}-1right)left(dfrac{1}{36}-1right)
Bleft(1-dfrac{1}{2^2}right)left(1-dfrac{1}{3^2}right)........left(1-dfrac{1}{10^2}right)
C1+dfrac{1}{2}+dfrac{1}{2^2}+dfrac{1}{2^3}+..........+dfrac{1}{2^{2016}}
Giúp mk nha!Cảm ơn rất nhìu!
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Tính
A=\(\left(\dfrac{1}{3}-1\right)\left(\dfrac{1}{6}-1\right)\left(\dfrac{1}{10}-1\right)\left(\dfrac{1}{15}-1\right)\left(\dfrac{1}{21}-1\right)\left(\dfrac{1}{28}-1\right)\left(\dfrac{1}{36}-1\right)\)
B=\(\left(1-\dfrac{1}{2^2}\right)\left(1-\dfrac{1}{3^2}\right)........\left(1-\dfrac{1}{10^2}\right)\)
C=\(1+\dfrac{1}{2}+\dfrac{1}{2^2}+\dfrac{1}{2^3}+..........+\dfrac{1}{2^{2016}}\)
Giúp mk nha!Cảm ơn rất nhìu!
Ta có: \(A=\left(\dfrac{1}{3}-1\right)\left(\dfrac{1}{6}-1\right)\left(\dfrac{1}{10}-1\right)\left(\dfrac{1}{15}-1\right)\left(\dfrac{1}{21}-1\right)\left(\dfrac{1}{28}-1\right)\left(\dfrac{1}{36}-1\right)\)
\(=\dfrac{-2}{3}.\dfrac{-5}{6}.\dfrac{-9}{10}.\dfrac{-14}{15}.\dfrac{-20}{21}.\dfrac{-27}{28}.\dfrac{-35}{36}\)
\(=\dfrac{-2.\left(-5\right).3.\left(-3\right).2.\left(-7\right).\left(-4\right).5.\left(-3\right).9.5.\left(-7\right)}{3.2.3.2.5.3.5.3.7.4.7.4.9}\)
\(=\dfrac{-5}{3.4}=\dfrac{-5}{12}\)
Vậy \(A=\dfrac{-5}{12}.\)
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\(C=1+\dfrac{1}{2}+\dfrac{1}{2^2}+\dfrac{1}{2^3}+...+\dfrac{1}{2^{2016}}\)
\(2C=2\left(1+\dfrac{1}{2}+\dfrac{1}{2^2}+\dfrac{1}{2^3}+...+\dfrac{1}{2^{2016}}\right)\)
\(2C=2+1+\dfrac{1}{2}+\dfrac{1}{2^2}+....+\dfrac{1}{2^{2015}}\)
\(2C-C=\left(2+1+\dfrac{1}{2}+...+\dfrac{1}{2^{2015}}\right)-\left(1+\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^{2016}}\right)\)
\(C=2-\dfrac{1}{2^{2016}}\)
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Tính :
a, dfrac{3cdot13-13cdot18}{15cdot40-80};
b, dfrac{18cdot34+left(-18right)cdot124}{-36cdot17+9cdotleft(-52right)};
c, dfrac{dfrac{3}{41}-dfrac{12}{47}+dfrac{27}{53}}{dfrac{4}{41}-dfrac{16}{47}+dfrac{36}{53}}+dfrac{-0,25cdotdfrac{-2}{3}-0,75:left(dfrac{-1}{2}+dfrac{2}{3}right)}{left|-1dfrac{1}{2}right|cdotleft(dfrac{-2}{3}-75%:dfrac{3}{-2}right)}.
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Tính :
a, \(\dfrac{3\cdot13-13\cdot18}{15\cdot40-80}\);
b, \(\dfrac{18\cdot34+\left(-18\right)\cdot124}{-36\cdot17+9\cdot\left(-52\right)}\);
c, \(\dfrac{\dfrac{3}{41}-\dfrac{12}{47}+\dfrac{27}{53}}{\dfrac{4}{41}-\dfrac{16}{47}+\dfrac{36}{53}}+\dfrac{-0,25\cdot\dfrac{-2}{3}-0,75:\left(\dfrac{-1}{2}+\dfrac{2}{3}\right)}{\left|-1\dfrac{1}{2}\right|\cdot\left(\dfrac{-2}{3}-75\%:\dfrac{3}{-2}\right)}\).
a: \(=\dfrac{13\left(3-18\right)}{40\left(15-2\right)}=\dfrac{13}{15-2}\cdot\dfrac{-15}{40}=\dfrac{-3}{8}\)
b: \(=\dfrac{18\left(34-124\right)}{36\left(-17-13\right)}=\dfrac{1}{2}\cdot\dfrac{-90}{-30}=\dfrac{3}{2}\)
c: \(=\dfrac{3\left(\dfrac{1}{41}-\dfrac{4}{47}+\dfrac{9}{53}\right)}{4\left(\dfrac{1}{41}-\dfrac{4}{47}+\dfrac{9}{53}\right)}+\dfrac{\dfrac{-1}{4}\cdot\dfrac{-2}{3}-\dfrac{3}{4}:\dfrac{1}{6}}{\dfrac{3}{2}\cdot\left(\dfrac{-2}{3}-\dfrac{3}{4}\cdot\dfrac{-2}{3}\right)}\)
\(=\dfrac{3}{4}+\dfrac{\dfrac{2}{12}-\dfrac{9}{2}}{\dfrac{3}{2}\cdot\dfrac{-1}{6}}=\dfrac{3}{4}+\dfrac{-13}{3}:\dfrac{-3}{12}=\dfrac{3}{4}+\dfrac{13}{3}\cdot\dfrac{12}{3}\)
\(=\dfrac{3}{4}+\dfrac{156}{9}=\dfrac{217}{12}\)
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Tính hợp lý
\(A = \left(1-\dfrac{1}{25}\right)\left(1-\dfrac{1}{36}\right)\left(1-\dfrac{1}{49}\right)...\left(1-\dfrac{1}{10000}\right)\) B= \(\left(1-\dfrac{1}{3}\right)\left(1-\dfrac{1}{6}\right)\left(1-\dfrac{1}{10}\right)...\left(1-\dfrac{1}{50.101}\right)\)
25 tháng 1 2022 lúc 14:01
1,dfrac{5left(x-1right)+2}{6}-dfrac{7x-1}{4x}dfrac{2left(2x+1right)}{7}-52,dfrac{3left(x-3right)}{4}+dfrac{4x-10,5}{10}dfrac{3
left(x+1right)}{5}+63,dfrac{2left(3x+1right)+1}{4}-5dfrac{2left(3x-1right)}{5}-dfrac{3x+2}{10}Diễn giải ra cho em với ạ!Em cảm ơn
Đọc tiếp
1,\(\dfrac{5\left(x-1\right)+2}{6}\)-\(\dfrac{7x-1}{4x}\)=\(\dfrac{2\left(2x+1\right)}{7}\)-5
2,\(\dfrac{3\left(x-3\right)}{4}\)+\(\dfrac{4x-10,5}{10}\)=\(\dfrac{3 \left(x+1\right)}{5}\)+6
3,\(\dfrac{2\left(3x+1\right)+1}{4}\)-5=\(\dfrac{2\left(3x-1\right)}{5}\)-\(\dfrac{3x+2}{10}\)
Diễn giải ra cho em với ạ!Em cảm ơn
1, bạn xem lại đề
2, 15(x-3) + 8x-21 = 12(x+1) +120
<=> 23x - 66 = 12x + 132
<=> 11x = 198 <=> x = 198/11
3, 10(3x+1) + 5 - 100 = 8(3x-1) - 6x - 4
<=> 30x + 10 - 95 = 18x -12
<=> 12x = 73 <=> x = 73/12
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