Question

If the sum of n terms of an ap is given by sn = a +bn + cn^2 where a, b, c are independent of n then n, then its common difference is

Answer 1

In the attachment I have answered this problem.

The common difference of an AP is found from

= term2 - term1

See the attachment for detailed solution.

Answer 2

Answer:

Step-by-step explanation:

Sn = a+bn+cn^2

S1 = a +b+c

S2 = a+ 2b+4c

a1 = b+c { here a = 0}

a2 = S2-S1

    =a+ 2b+4c-a-b-c

    = b+3c

d= a2-a1

 = b+3c-b-c

 = 2c