\(B=\frac{3}{5.8}+\frac{3}{8.11}+...+\frac{3}{2018.2021}\)
\(B=\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+...+\frac{1}{2018}-\frac{1}{2021}\)
\(B=\frac{1}{5}-\frac{1}{2021}\)
\(B=\frac{2016}{10105}\)
Tính : \(\frac{3}{2.5}+\frac{3}{5.8}+\frac{3}{8.11}+\frac{3}{11.14}+\frac{3}{14.17}\)
Tính : \(A=\frac{3}{5.8}+\frac{3}{8.11}+\frac{3}{11.14}+...+\frac{3}{2009.2012}+\frac{3}{2012.2015}\)
Tính tổng:
\(\frac{3}{5.8}+\frac{3}{8.11}+\frac{3}{11.14}+...+\frac{3}{21.24}\)
\(\frac{3^2}{2.5}+\frac{3^2}{5.8}+\frac{3^2}{8.11}+\frac{3^2}{11.14}+\frac{3^2}{14.172}\)
Tính H=\(\frac{3^2}{1.5}+\frac{3^2}{5.8}+\frac{3^2}{8.11}+\frac{3^2}{11.14}+...+\frac{3^2}{197.200}\)
Tìm x, biết
1, \(x+\frac{3}{5.8}+\frac{3}{8.11}+\frac{3}{11.14}+...+\frac{3}{32.35}=\frac{-29}{35}\)
Tìm x , biết : \(\frac{1}{5.8}+\frac{1}{8.11}+\frac{1}{11.14}+...+\frac{1}{x.(x+3)}=\frac{101}{1504} \)
Tìm x
\(\frac{1}{5.8}+\frac{1}{8.11}+\frac{1}{11.14}+...+\frac{1}{x\left(x+3\right)}=\frac{101}{1540}\)
1) Tính nhanh:
a) A = \(\frac{3}{2}+\frac{3}{6}+\frac{3}{12}+\frac{3}{20}+....+\frac{3}{90}\)
b) B = \(\frac{2}{2.5}+\frac{2}{5.8}+\frac{2}{8.11}+\frac{2}{11.14}+\frac{2}{14.17}\)
Lưu ý: Dấu chấm là dấu nhân nha mọi người
