If the sum of $n$ terms of an A.P. is given by $S_n = 3n^2 + 5n$, then find its 2nd term.
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Question

If the sum of $n$ terms of an A.P. is given by $Sn = 3n^2 + 5n$, then find its 2nd term.

Accepted Answer

The second term of an A.P. can be found using the relation $a2 = S2 - S1$. First, calculate $S1$ (which is equal to $a1$): $S1 = 3(1)^2 + 5(1) = 3 + 5 = 8$. Next, calculate $S2$: $S2 = 3(2)^2 + 5(2) = 3(4) + 10 = 12 + 10 = 22$. Now, $a2 = S2 - S1 = 22 - 8 = 14$. Therefore, the correct option is B.

Sequences and Series

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