If `S_(n)` denotes sum of first `n` terms of a `G.P.` of real numbers with common ratio `r` ,where first term is independent of `r` ,then `((r-1))(d(S_(n)))/(dr)` is equal to

If S_(n) denotes the sum of n terms of an A.P. whose common difference is d and first term is a,find S_(n)-2S_(n-1)+S_(n-2)

If S is the sum to infinite terms of a G.P.whose first term is 'a',then the sum of the first n terms is

if S_(n) denotes the sum of n terms of a G.P whose first term is a and common ratio is r then find the sum of S_(1),S_(3),S_(5).........,S_(2)n-1

Let S_(n) be the sum of first n terms of an A.P. with non-zero common difference.Fine the ratio of first term and common difference if (S_(n_(1)n_(2)))/(S_(n_(1))) is independent of n_(1)

If S_(n)=n^(2)a+(n)/(4)(n-1)d is the sum of first n terms of A.P.then common differnce is

Let S_(n) denote the sum of first n terms of an A.P.If S_(2n)=3S_(n), then find the ratio S_(3n)/S_(n)

Let S_(n) denote the sum of the cubes of the first n natural numbers and s_(n) denote the sum of the first n natural numbers.Then sum_(r=1)^(n)(S_(r))/(s_(r)) is equal to

let S_(n) denote the sum of the cubes of the first n natural numbers and s_(n) denote the sum of the first n natural numbers , then sum_(r=1)^(n)(S_(r))/(s_(r)) equals to