Question
Question: If S<sub>n</sub> denotes the sum of n terms of an A.P., then S<sub>n+3</sub> – 3S<sub>n+2</sub> + 3...
If Sn denotes the sum of n terms of an A.P., then Sn+3 –
3Sn+2 + 3Sn+1 – Sn =
A
0
B
l
C
21
D
2
Answer
0
Explanation
Solution
Sn+3 – 3Sn+2 – 3Sn+1 – Sn
= (Sn+3 – Sn+2) –2(Sn+2 – Sn–1) + (Sn+1 – Sn)
= Tn+3 – 2Tn+2 + Tn+1
= (Tn+3 – Tn+2) – (Tn+2 – Tn+1)
= d – d = 0.