Question

In an AP sn=2n^2+3n find the AP

Answer 1

Given,
Sn=2n^2+3n
Put n=1,
Then,
S(1)=2*1^2+3*1=5= first term of required AP ;t(1)
Put n=2,
Then,
S(2)=2*2^2+3*2=17
Now, s(2)-s(1) second term of required AP
t(2)=12
Now, common difference=t(2)-t(1)=12-5=7
Thus required AP= 5,12,19,26.....

Hope it helps you.....