Progression (Sequence and Series)Hard
Question
The sum of the first n terms of the series 12 + 2 . 22 + 32 + 2 . 42 + 52 + 2 . 62 + ... is 
when n is even. When n is odd the sum is
when n is even. When n is odd the sum isOptions
A.
B.
C.
D.
Solution
If n is odd then (n - 1) is even ⇒ sum of odd terms 
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