Question

E=3^2/8*11+3^2/11*14+3^2/14*17+...+3^2/197*200

Hộ  xíu caccau ơi ~~~

 

Answer 1

\(E=\frac{3^2}{8.11}+\frac{3^2}{11.14}+\frac{3^2}{14.17}+...+\frac{3^2}{197.200}\)

\(=\frac{9}{8.11}+\frac{9}{11.14}+\frac{9}{14.17}+...+\frac{9}{197.200}\)

\(\Rightarrow\frac{1}{3}.E=\frac{3}{8.11}+\frac{3}{11.14}+\frac{3}{14.17}+...+\frac{3}{197.200}\)

\(=\frac{1}{8}-\frac{1}{11}+\frac{1}{11}-\frac{1}{14}+\frac{1}{14}-\frac{1}{17}+...+\frac{1}{197}-\frac{1}{200}\)

\(=\frac{1}{8}-\frac{1}{200}=\frac{3}{25}\)

\(\Rightarrow E=\frac{3}{25}\div\frac{1}{3}=\frac{9}{25}\)