Question

Find 2nd term of series if the sum of first n terms be 5n2+ 2n

Answer 1

nth term, Tn = Sn - Sn-1
So, T2 = S2 - S1
$= (5 \times {2}^{2} + 2 \times 2) - (5 \times {1}^{2} + 2 \times 1) \\ = 24 - 7 = 17$