If the sum of n terms of an arithmetic progression is $$2n^2 +5n$$, then its nth term is

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Uniteasy Admin · Accepted Answer

Since  the sum of n terms of an arithmetic progression is $$2n^2 +5n$$
$$S_n = 2n^2 +5n$$
then
$$S_{n-1} = 2(n-1)^2+5(n-1)$$
$$a_n = S_n-S_{n-1}$$
$$=2n^2 +5n- 2(n-1)^2+5(n-1)$$
$$=4n+3$$
Therefore, C is correct

Multiple Choice Question (MCQ)

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