\(3S=3\left(\frac{1}{2.5}+....+\frac{1}{\left(3n+1\right)\left(3n+2\right)}\right)\)
Đến đây thì bạn làm như dạng đơn giản nhé
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Tìm x biết: \(\left(\frac{1}{2\cdot5}+\frac{1}{5\cdot8}+\frac{1}{8\cdot11}+...+\frac{1}{65\cdot68}\right)x-\frac{7}{34}=\frac{19}{68}\)
Tìm x biết :\(\left(\frac{1}{2\cdot5}+\frac{1}{5\cdot8}+\frac{1}{8\cdot11}+...+\frac{1}{65\cdot68}\right)x-\frac{7}{34}=\frac{19}{68}\)
Tìm x biết: \(\left(\frac{1}{2\cdot5}+\frac{1}{5\cdot8}+\frac{1}{8\cdot11}+...+\frac{1}{65\cdot68}\right)x-\frac{7}{34}=\frac{19}{68}\)
Tìm số nguyên âm a biết:
\(a^2-\left(\frac{3}{5}\right)^2=\frac{1}{1\cdot2}+\frac{1}{2\cdot7}+\frac{1}{7\cdot5}+\frac{1}{5\cdot13}+\frac{1}{13\cdot8}+\frac{1}{8\cdot19}+\frac{1}{19\cdot11}+\frac{1}{11\cdot25}\)
Tìm số nguyên âm a biết:
\(a^2-\left(\frac{3}{5}\right)^2=\frac{1}{1\cdot2}+\frac{1}{2\cdot7}+\frac{1}{7\cdot5}+\frac{1}{5\cdot13}+\frac{1}{13\cdot8}+\frac{1}{8\cdot19}+\frac{1}{19\cdot11}+\frac{1}{11\cdot25}\)
Tìm số nguyên dương a thoả mãn:
\(a^2-\left(\frac{3}{5}\right)^2=\frac{1}{1\cdot2}+\frac{1}{2\cdot7}+\frac{1}{7\cdot5}+\frac{1}{5\cdot13}+\frac{1}{13\cdot8}+\frac{1}{8\cdot19}+\frac{1}{19\cdot11}+\frac{1}{11\cdot25}\)
Ai làm nhanh nhất thì mình tick cho
1/ Tính:a) frac{1}{2}-2left(frac{1}{2cdot4}+frac{1}{4cdot6}+frac{1}{6cdot8}+...+frac{1}{48cdot50}right)b) frac{-1}{3}+frac{-1}{15}+frac{-1}{63}+...+frac{-1}{9999}c) frac{8}{9}-frac{1}{72}-frac{1}{56}-frac{1}{42}-...-frac{1}{6}-frac{1}{2}d) 1-frac{1}{2cdot5}-frac{1}{5cdot8}-frac{1}{8cdot11}-...-frac{1}{89cdot92}-frac{1}{92cdot95}2/ Tìm x:3x-frac{1}{3}-frac{1}{15}-frac{1}{35}-frac{1}{63}-frac{1}{99}0
Đọc tiếp
1/ Tính:
a) \(\frac{1}{2}-2\left(\frac{1}{2\cdot4}+\frac{1}{4\cdot6}+\frac{1}{6\cdot8}+...+\frac{1}{48\cdot50}\right)\)
b) \(\frac{-1}{3}+\frac{-1}{15}+\frac{-1}{63}+...+\frac{-1}{9999}\)
c) \(\frac{8}{9}-\frac{1}{72}-\frac{1}{56}-\frac{1}{42}-...-\frac{1}{6}-\frac{1}{2}\)
d) \(1-\frac{1}{2\cdot5}-\frac{1}{5\cdot8}-\frac{1}{8\cdot11}-...-\frac{1}{89\cdot92}-\frac{1}{92\cdot95}\)
2/ Tìm x:
\(3x-\frac{1}{3}-\frac{1}{15}-\frac{1}{35}-\frac{1}{63}-\frac{1}{99}=0\)
Bài 1: Tìm n1/4*2/6*3/8*4/10*5/12*.....* 30/62*31/642^nBài 2: Tínha) frac{left(-5right)^{60}cdot30^5}{15^5cdot5^{61}} b)2^3+3cdotleft(frac{1}{3}right)^0-2^{-2}cdot4+left[left(-2right)^3:frac{1}{2}right]cdot8(GỢI Ý CÂU B:^{2^{-2}frac{1}{2^2}}Bài 3: Tìm xa)^{2^x16}b)^{left(frac{x}{13}right)^2frac{49}{169}}c)left(frac{-1}{5}right)^xleft(frac{-1}{125}right)^3cdot x^4frac{-16}{625}d)^{6^{4-x}216}Bài 4:Tìm na)3^ncdot3^{-2}3^5b)Tìm x:1)frac{2^{4-x}}{16^5}32^62)^{9cdot5^x6cdot5^6+3cdot5^6}3)frac{2^3}{2...
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Bài 1: Tìm n
1/4*2/6*3/8*4/10*5/12*.....* 30/62*31/64=2^n
Bài 2: Tính
a) \(\frac{\left(-5\right)^{60}\cdot30^5}{15^5\cdot5^{61}}\)
b)\(2^3+3\cdot\left(\frac{1}{3}\right)^0-2^{-2}\cdot4+\left[\left(-2\right)^3:\frac{1}{2}\right]\cdot8\)
(GỢI Ý CÂU B:\(^{2^{-2}=\frac{1}{2^2}}\)
Bài 3: Tìm x
a)\(^{2^x=16}\)
b)\(^{\left(\frac{x}{13}\right)^2=\frac{49}{169}}\)
c)\(\left(\frac{-1}{5}\right)^x=\left(\frac{-1}{125}\right)^3\cdot x^4=\frac{-16}{625}\)
d)\(^{6^{4-x}=216}\)
Bài 4:Tìm n
a)\(3^n\cdot3^{-2}=3^5\)
b)Tìm x:
1)\(\frac{2^{4-x}}{16^5}=32^6\)
2)\(^{9\cdot5^x=6\cdot5^6+3\cdot5^6}\)
3)\(\frac{2^3}{2^x}=4^5\)
Các bạn giúp mik!!!Mik sắp kiểm tra 45p r
CMR với n thuộc Z, ta có:
\(\left(1+\frac{1}{2}\right).\left(1+\frac{1}{5}\right).\left(1+\frac{1}{9}\right)...\left(1+\frac{2}{n^2+3n}\right)< 3\)