If `S_n` denotes the sum of first ‘n’ naturalnumbers, then `S_1 +S_2x+S_3x^2 +........+S_n x^(n-1) +....oo=`

If S_(n) denotes the sum of first 'n' natural numbers then S_(1)+S_(2)x+S_(3)x^(2)+........+S_(n)*x^(n-1)+.....oo= then n is

If S_(n) denotes the sum of first 'n' natural numbers then s_(1)+S_(2)x+S_(3)x^(2)+.........+S_(n) x^(n-1)+......oo=(1-x)^(-n) then n is

If s_(n) denotes the sum of first 'n' natural numbers then S_(1)+S_(2)x+S_(3)x^(2)+.........+S_(n)x^(n-1)+......oo=(1-x)^(-n) then n is

If S_n denotes the sum of first n natural number then S_1 + S_2x + S_3 x^2 +……+S_n x^(n-1) + ……oo terms =

If S_n denotes the sum of first n natural number then S_1 + S_2x + S_3 x^2 +……+S_n x^(n-1) + ……oo terms =

If S_(n) denotes the sum of first 'n' natural numbers then S_(1)+S_(2)x+S_(3)x^(2)+........+S_(n)*x^(n-1)+.. then n is

If S_(n) denotes the sum of first 'n' natural numbers then S_(1)+S_(2)x+S_(3)x^(2)+........+S_(n)*x then n is

If S_n denotes the sum of first n terms of an AP, prove that S_(12) = 3 (S_(8) -S_4)

If S_(n) denotes the sum of first n terms of an A.P., then (S_(3n)-S_(n-1))/(S_(2n)-S_(n-1)) is equal to

Let S_n denote the sum of first n terms of an A.P. and S_2n = 3S_n then ratio of S_3n : S_n