Question

[Aries của 6b]

TÝnh:

N = 3²/8.11  +  3²/11.14  +  3²/14.17  + ...+3²/197.200.

Answer 1

[Nguyễn Tuấn Minh]

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

Answer 2

[Đinh Đức Hùng]

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

\(\Rightarrow N=\frac{9}{3}\left(\frac{1}{8}-\frac{1}{11}+\frac{1}{11}-\frac{1}{14}+...+\frac{1}{197}-\frac{1}{200}\right)\)

\(\Rightarrow N=3\left(\frac{1}{8}-\frac{1}{200}\right)=\frac{3}{8}-\frac{3}{200}=\frac{75}{200}-\frac{3}{200}=\frac{72}{200}=\frac{9}{25}\)