Violympic toán 7
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H24
30 tháng 9 2023 lúc 15:00
tính tỉ số \(\dfrac{A}{B}\) biết A=\(\dfrac{1}{1.2}\)+\(\dfrac{1}{3.4}\)+...+\(\dfrac{1}{101.102}\) và B=\(\dfrac{1}{52.102}\)+\(\dfrac{1}{53.101}\)+...+\(\dfrac{1}{102.52}\)+\(\dfrac{2}{77.154}\)
\(tính:\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{4}-\dfrac{1}{5}+\dfrac{1}{6}-\dfrac{1}{7}+\dfrac{1}{8}+\dfrac{1}{7}-\dfrac{1}{6}+\dfrac{1}{5}-\dfrac{1}{4}+\dfrac{1}{3}-\dfrac{1}{2}\)
\(\dfrac{1}{2}+\dfrac{1}{6}+\dfrac{1}{12}+\dfrac{1}{20}+\dfrac{1}{30}+\dfrac{1}{42}+\dfrac{1}{56}+\dfrac{1}{72}\).Tính
DX
2 tháng 7 2021 lúc 21:10
Tính giá trị biểu thức A , biết rằng A M : N Mà M dfrac{dfrac{1}{99}+dfrac{2}{98}+dfrac{3}{97}+dfrac{4}{96}+...+dfrac{97}{3}+dfrac{98}{2}+dfrac{99}{1}}{dfrac{1}{2}+dfrac{1}{3}+dfrac{1}{4}+dfrac{1}{5}+dfrac{1}{6}+...+dfrac{1}{100}} N dfrac{92-dfrac{1}{9}-dfrac{2}{10}-dfrac{3}{11}-...-dfrac{90}{98}-dfrac{91}{99}-dfrac{92}{100}}{dfrac{1}{45}+dfrac{1}{50}+dfrac{1}{55}+...+dfrac{1}{495}+dfrac{1}{500}}
Đọc tiếp
Tính giá trị biểu thức A , biết rằng A = M : N
Mà M = \(\dfrac{\dfrac{1}{99}+\dfrac{2}{98}+\dfrac{3}{97}+\dfrac{4}{96}+...+\dfrac{97}{3}+\dfrac{98}{2}+\dfrac{99}{1}}{\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{1}{6}+...+\dfrac{1}{100}}\)
N = \(\dfrac{92-\dfrac{1}{9}-\dfrac{2}{10}-\dfrac{3}{11}-...-\dfrac{90}{98}-\dfrac{91}{99}-\dfrac{92}{100}}{\dfrac{1}{45}+\dfrac{1}{50}+\dfrac{1}{55}+...+\dfrac{1}{495}+\dfrac{1}{500}}\)
8) Adfrac{9}{10}-dfrac{1}{90}-dfrac{1}{72}-dfrac{1}{56}-dfrac{1}{42}-dfrac{1}{30}-dfrac{1}{20}-dfrac{1}{12}-dfrac{1}{6}-dfrac{1}{2}
9) Bdfrac{1}{3}+dfrac{1}{3^2}+dfrac{1}{3^4}+...+dfrac{1}{3^{2014}}+dfrac{1}{3^{2015}}
10) Pdfrac{dfrac{1}{2}+dfrac{1}{3}+dfrac{1}{4}+...+dfrac{1}{2005}}{dfrac{2004}{1}+dfrac{2003}{2}+dfrac{2002}{3}+...+dfrac{1}{2004}}
Đọc tiếp
8) \(A=\dfrac{9}{10}-\dfrac{1}{90}-\dfrac{1}{72}-\dfrac{1}{56}-\dfrac{1}{42}-\dfrac{1}{30}-\dfrac{1}{20}-\dfrac{1}{12}-\dfrac{1}{6}-\dfrac{1}{2}\)
9) \(B=\dfrac{1}{3}+\dfrac{1}{3^2}+\dfrac{1}{3^4}+...+\dfrac{1}{3^{2014}}+\dfrac{1}{3^{2015}}\)
10) \(P=\dfrac{\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{2005}}{\dfrac{2004}{1}+\dfrac{2003}{2}+\dfrac{2002}{3}+...+\dfrac{1}{2004}}\)
Tính giá trị của biểu thức : A = \(\dfrac{1}{2}+\dfrac{1}{14}+\dfrac{1}{35}+\dfrac{1}{65}+\dfrac{1}{104}+\dfrac{1}{152}+\dfrac{1}{209}+\dfrac{1}{275}\)
H24
30 tháng 9 2023 lúc 15:19
tính B=\(\dfrac{1}{99.97}\)-\(\dfrac{1}{97.95}\)-...-\(\dfrac{1}{5.3}\)-\(\dfrac{1}{3.1}\)
Tính :
A dfrac{2}{60.63}+dfrac{2}{63.66}+..........+dfrac{2}{107.120}+dfrac{2}{2006}.
B dfrac{5}{40.44}+dfrac{5}{44.48}+.....+dfrac{5}{76.80}+dfrac{5}{2006}.
C dfrac{1}{10}+dfrac{1}{40}+dfrac{1}{88}+dfrac{1}{154}+dfrac{1}{238}+dfrac{1}{340}.
D dfrac{1}{3}+dfrac{1}{6}+dfrac{1}{10}+dfrac{1}{15}+.........+dfrac{1}{2015.2018}
Đọc tiếp
Tính :
A = \(\dfrac{2}{60.63}+\dfrac{2}{63.66}+..........+\dfrac{2}{107.120}+\dfrac{2}{2006}\).
B = \(\dfrac{5}{40.44}+\dfrac{5}{44.48}+.....+\dfrac{5}{76.80}+\dfrac{5}{2006}\).
C = \(\dfrac{1}{10}+\dfrac{1}{40}+\dfrac{1}{88}+\dfrac{1}{154}+\dfrac{1}{238}+\dfrac{1}{340}\).
D = \(\dfrac{1}{3}+\dfrac{1}{6}+\dfrac{1}{10}+\dfrac{1}{15}+.........+\dfrac{1}{2015.2018}\)
Tính tổng đại số
\(A=\dfrac{1}{2}-\dfrac{1}{3}-\dfrac{2}{3}+\dfrac{1}{4}+\dfrac{2}{4}+\dfrac{3}{4}-\dfrac{1}{5}-\dfrac{2}{5}-\dfrac{3}{5}-\dfrac{4}{5}+...+\dfrac{1}{10}+\dfrac{2}{10}+...+\dfrac{9}{10}\)
\(B=\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{2}{3}+\dfrac{1}{4}+\dfrac{2}{4}+\dfrac{3}{4}+...+\dfrac{1}{n}+\dfrac{2}{n}+...+\dfrac{n-1}{n}\)\(\left(n\in Z,n\ge2\right)\)