[" a fere "S_(2)=8ftl" I "S_(4)=80kt" it attal "xam],[=8" and "S_(4)=80." find its first term and the "]

If for a G.P., S_(2) =8 and S_(4) =80 , then : (a,r) -=

Let there be an A.P.with first term a', common difference 'd'. If a_(n) denotes its nth term and S_(n) the sum of first n terms,find n and a_(n), if a=2,quad d=8 and S_(n)=90

Let there be an A.P.with first term 'a' common difference 'd'. If a_(n) denotes its nth term and S_(n) the sum of first n terms,find n and d, if a=8,a_(n)=62 and S_(n)=210

Let there be an A.P.with first term a', common difference 'd'. If a_(n) denotes its nth term and S_(n) the sum of first n terms,find n and a, if a_(n)=4,quad d=2 and S_(n)=-14

Let S_(n) denote the sum of first n terms of an A.P. If S_(4) = -34 , S_(3) = - 60 and S_(6) =- 93 , then the common difference and the first term of the A.P. are respectively.

The sum of an infinite GP is 80/9 and its common ratio is (-4)/5 . Find its first term.

The sum of an infinite G.P. is 80/9 and its common ration is -4/5. Find its first term.

Let S_(1) be the sum of the first n terms of the A.P 8,12,16,... and let S_(2) be the sum of the first n terms of the A.P 17,19,21,... assume n!=0 then S_(1)=S_(2) for

Find S_(5) of the A.P. 8,6,4,….

If S_(1) = {2}, S_(2) = {3,6}, S_(3) = {4,8,16}, S_(4) = { 5,10, 20, 40}, …...... then the sum of numbers in the set S_(15) is