Question

if the sum of n terms of an a.p is given by sn=3n+2n^2, then the common difference of the a.p is​

Answer 1

Answer:

4

Step-by-step explanation:

Sn= 3n+2n^2

Sum of n terms= (n/2)(2a+(n-1)d)

Sum of first 2 terms= 14

(2/2) (2a+d)= 14 ...(i)

Sum of first 3 terms= 27

(3/2) (2a+2d)...(ii)

On solving the above two equations we get a=5 & d=4