A) \[\frac{2}{7}\]
B) \[\frac{6}{7}\]
C) \[\frac{8}{7}\]
D) \[\frac{1}{7}\]
Correct Answer: D
Solution :
(d): \[\frac{1}{2}\left( \frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}+\frac{1}{11}-\frac{1}{13}+\frac{1}{13}-\frac{1}{15}+\frac{1}{15}-\frac{1}{17}+\frac{1}{17}-\frac{1}{19}+\frac{1}{19}-\frac{1}{21}+\frac{1}{21} \right)\] \[=\frac{1}{2}\left( \frac{1}{3}-\frac{1}{21} \right)\] \[=\frac{1}{2}\left( \frac{7-1}{21} \right)=\frac{1}{2}\times \frac{6}{21}=\frac{1}{7}\]
You need to login to perform this action.
You will be redirected in
3 sec
