Question

If sum of n terms of an A.P. is given by Sn = 2n^2 - n then find its common difference . PLEASE HELP

Answer 1

common difference =4

Answer 2

Hey mate here is ur answer:

Sn=2n^2-1

Put n=1

S1=2×1^2-1

=2-1

=1

So first term of the AP (a1) = 1

Put n=2

S2=2×2^2-2

=8-2

=6

Then a1+a2=6

1+a2=6

a2=6-1

a2=5

Now the common difference,d is :

a2-a1 = 5-1

d = 4

Hope it helps!!

@dph