N=3(3/8.11 +3 /11.14 + 3/14.17 +...+3/197.200)
N=3( 1/8-1/11+1/11-1/14+1/14-1/17+...+1/197-1/200)
N=3(1/8-1/200)
N=3. 3/25=9/25
Ủng hộ mk nha
\(\Rightarrow N=\frac{9}{8.11}+\frac{9}{11.14}+\frac{9}{14.17}+....+\frac{9}{197.200}\)
\(\Rightarrow N=\frac{9}{3}\left(\frac{1}{8}-\frac{1}{11}+\frac{1}{11}-\frac{1}{14}+...+\frac{1}{197}-\frac{1}{200}\right)\)
\(\Rightarrow N=3\left(\frac{1}{8}-\frac{1}{200}\right)=\frac{3}{8}-\frac{3}{200}=\frac{75}{200}-\frac{3}{200}=\frac{72}{200}=\frac{9}{25}\)
N = 32/8.11 + 32/11.14 + 32/14.17 + ...+32/197.200.
