Mark the correct alternative in the following:
If 
are in A.P. with common difference d, then the sum of the series 
, is
Here,a1, a2,…,an are in A.P.
Then d=a2-a1=a3-a2=…=an-an-1
1
Mark the correct alternative in the following:
If are in A.P. with common difference d, then the sum of the series , is
Here,a1, a2,…,an are in A.P.
Then d=a2-a1=a3-a2=…=an-an-1