Question

If sum of n terms of an AP is given by sn=2n^2-n then find its common difference.

Answer 1

Answer:

Step-by-step explanation:

$S_{n}=n/2[2a+(n-1)d] =2n^{2}-n;\\ n[2a+(n-1)d]=4n^{2}-2n;\\ 2a+(n-1)d=4n-2;........(i)\\ \\\\\\a=2(1)^{2} -1=2-1=1.....(ii)\\Substituting (ii)in (i)\\2(1)+(n-1)d=4n-2\\(n-1)d=4n-4\\(n-1)d=4(n-1)\\Therefore d=4;$