Question

Tính B= \(\frac{1}{16}\)+ \(\frac{6}{16.26}\)+\(\frac{6}{26.36}\)+...........+\(\frac{6}{2006.2016}\)

Answer 1

\(B=\frac{1}{16}+\frac{6}{16.26}+\frac{6}{26.36}+...+\frac{6}{2006.2016}\)

\(B=\frac{1}{16}+6\left(\frac{1}{16.26}+\frac{6}{26.36}+...+\frac{6}{2006.2016}\right)\)

\(B=\frac{1}{16}+\frac{6}{10}\left(\frac{1}{16}-\frac{1}{26}+\frac{1}{26}-\frac{1}{36}+...+\frac{1}{2006}-\frac{1}{2016}\right)\)

\(B=\frac{1}{16}+\frac{6}{10}\left(\frac{1}{16}-\frac{1}{2016}\right)\)

\(B=\frac{1}{16}+\frac{6}{10}.\frac{125}{2016}\)

\(B=\frac{1}{16}+\frac{25}{672}\)

\(B=\frac{67}{672}\)