Question

the sum of first n terms of an ap is given by Sn=2n^2+3n. Find the 16th term of AP

Answer 1

Sn=n/2{2a+(n-1)d
2n^2+3n=n/2(2a+(n-1)d

Here n=1
then a=5....(aftr computing)

also n=2
then d=4....(aftr computing)

now,
16th term = a+15d

5+15(4)= 65


hope it helps..