If pth,qth and rth terms of an A.P. are a,b,c respectively, then find the value of:
(a−b)r+(b−c)p+(c−a)q
Let us consider
First term =A
Common difference =D
then a=A+(p−1)D
b=A+(q−1)D
c=A+(r−1)D
Given
(a−b)r+(b−c)p+(c−a)q
=[A+(p−1)D−A−(q−1)D]r+[A+(q−1)D−A−(r−1)D]p+[A+(r−1)D−A−(p−1)D]q
=(p−q)Dr+(q−r)Dp+(r−p)Dq
=D[pr−qr+qp−rp+rq−pq]
=D(0)=0