Question

if the sum of n term of a series be 2n2 + 7 n.find the first 5 terms of progression

Answer 1

Just giving the way to do

Hope you will get it

Given

Sn =...

To get

First term I.e.

S1= a1 = just place the value as n=1

For a2 use formula a3=S2 - S1

Like this for a3 = S3-S2

Like this you can find upto a5