Answer:
n = n
First term, a = a1 = (x-y)/(x+y)
Common difference, d = a2 – a1 = (3x – 2y)/(x + y) – (x-y)/(x+y) = (2x – y)/(x+y)
By using the formula,
S = n/2 (2a + (n – 1) d)
Substitute the values of ‘a’ and ‘d’, we get
S = n/2 (2((x-y)/(x+y)) + (n-1) ((2x – y)/(x+y)))
S = n/2(x+y) {n (2x-y) – y}
∴ The sum of the given AP is n/2(x+y) {n (2x-y) – y}