The sum of the series
is
is
- (A)
- (B)✓ Correct
- (C)
- (D)
Answer: (B)
Solution
Put in the expansion to get . The symmetry lets this alternating total be written as twice the partial sum up to the ninth term plus the central term . Solving, .
JEE Main · 2007 · 29 Apr 2007 · Offline · Single correct option