The common difference of an A.P., the sum of whose n terms is Sn, is
A. Sn - 2Sn - 1 + Sn - 2
B. Sn - 2Sn - 1 - Sn - 2
C. Sn - Sn - 2
D. Sn - Sn - 1
Answer: Option A
Solution(By Examveda Team)
Sum of n terms = Sn∴ an = Sn - Sn - 1
and an - 1 = Sn - 1 - Sn - 2
∴ Common difference (d) = an - an - 1
= (Sn - Sn - 1) - (Sn - 1 - Sn - 2)
Sn - Sn - 1 - Sn - 1 + Sn - 2
= Sn - 2Sn - 1 + Sn - 2
Related Questions on Progressions
Find the first term of an AP whose 8th and 12th terms are respectively 39 and 59.
A. 5
B. 6
C. 4
D. 3
E. 7
The sum of the first 16 terms of an AP whose first term and third term are 5 and 15 respectively is
A. 600
B. 765
C. 640
D. 680
E. 690
Join The Discussion