A = 3/2x5 + 3/5x8 + 3/8x11 + 3/11x14 + 3/14x17
A = 1/2 - 1/5 + 1/5 - 1/8 + 1/8 - 1/11 + 1/11 - 1/14 + 1/14 - 1/17
A = 1/2 - 1/17
A = 15/34
Ủng hộ mk nha ^_-
Ta có:
\(A=\frac{3}{2.5}+\frac{3}{5.8}+\frac{3}{8.11}+\frac{3}{11.14}+\frac{3}{14.17}\)
\(A=\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+\frac{1}{11}-\frac{1}{14}+\frac{1}{14}-\frac{1}{17}\)
\(A=\frac{1}{2}-\frac{1}{17}\)
\(A=\frac{17-2}{34}=\frac{15}{34}\)
Ủng hộ mk nha,chúc bn học tốt !!!
\(A\times3=\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+...+\frac{1}{14}-\frac{1}{17}\)
\(A\times3=\frac{1}{2}-\frac{1}{17}\)
\(A\times3=\frac{15}{34}\)
\(A=\frac{15}{34}\div3\)
\(A=\frac{15}{102}=\frac{5}{34}\)
Vậy \(A=\frac{5}{34}\)
Mk lm nhầm nha :(((
\(A=\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+...+\frac{1}{14}-\frac{1}{17}\)
\(A=\frac{1}{2}-\frac{1}{17}\)
\(A=\frac{15}{34}\)
Vậy \(A=\frac{15}{34}\)
\(A=\frac{3}{2.5}+\frac{3}{5.8}+\frac{3}{8.11}+.....+\frac{3}{14.17}\)
\(=\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+....+\frac{1}{14}-\frac{1}{17}\)
\(=\frac{1}{2}-\frac{1}{17}=\frac{15}{34}\)
A = \(\frac{3}{2.5}\)+\(\frac{3}{5.8}\)+\(\frac{3}{8.11}\)+..........+\(\frac{3}{14.17}\)
A = \(\frac{1}{2}\)-\(\frac{1}{5}\)+\(\frac{1}{8}\)-\(\frac{1}{11}\)+...............+\(\frac{1}{14}\)-\(\frac{1}{17}\)
A = \(\frac{1}{2}\)-\(\frac{1}{17}\)
A = \(\frac{15}{34}\)
