If the sum of first terms of an A.P. is , then the sum of squares of these terms is
- (A)
- (B)
- (C)✓ Correct
- (D)
Answer: (C)
Solution
Given , the -th term is .
Then .
The sum of squares is:
Simplifying:
Then .
The sum of squares is:
Simplifying:
JEE Advanced · 2009 · 12 Apr 2009 · Paper 2 · Single correct option