" 29If "T_(n)=6n+5," then find "S_(n)?

IF T_n=5n-2 , then find S_4 .

Let S_(n) be the sum of first n terms of and A.P. If S_(3n)=5S_(n) , then find the value of (S_(5n))/(S_(n)) is.

If t+n=sum_(1)^(n)n then find t_(n)^( prime)=sum_(1)^(n)t_(n)

t_ (n) = 3-4n, find S_ (20)

If S_(n) denotes the sum of first n terms of an A.P. If S_(2n) = 5(S_n) , then prove (S_(6n))/(S_(3n))=17/8

If t_n = 6n + 5 , then t_(n+1) =_________.

In an A.P, a=8 , t_n=62 , S_n=210 , then find n . a) 5 b) 6 c) 7 d) 8

If for a sequence (T_(n)), (i) S_(n) = 2n^(2)+3n+1 (ii) S_(n) =2 (3^(n)-1) find T_(n) and hence T_(1) and T_(2)

If t_(n)=(n+2)/((n+3)!) then find the value of sum_(n=5)^(20)t_(n)

In an A.P.if S_(1)=T_(1)+T_(2)+T_(3)+....+T_(n)(nodd)dot S_(2)=T_(2)+T_(4)+T_(6)+.........+T_(n) then find the value of S_(1)/S_(2) in terms of n.