If `S_r` denotes the sum of r terms of an A.P. and `S_a/a^2=S_b/b^2=c`. Then `S_c=` (A) `c^3` (B) `c/ab` (C) `abc` (D) `a+b+c`

S_(r) denotes the sum of the first r terms of an AP.Then S_(3d):(S_(2n)-S_(n)) is -

If S _(r) denote the sum of first 'r' terms of a non constaint A.P. and (S_(a ))/(a ^(2)) =(S_(b))/(b ^(2))=c, where a,b,c are distinct then S_(c) =

If S_r denotes the sum of the first r terms of an A.P. Then, S_(3n)\ :(S_(2n)-S_n) is n (b) 3n (c) 3 (d) none of these

If in an A.P., S_n=n^2p and S_m=m^2p , where S_r denotes the sum of r terms of the A.P., then S_p is equal to 1/2p^3 (b) m n\ p (c) p^3 (d) (m+n)p^2

If in an A.P.S_(n)=n^(2)q and S_(m)=m^(2)q, where S_(r) denotes the sum of r terms of the A.P.then S_(q) equals (q^(3))/(2) b.mnq c.q^(3) d.(m^(2)+n^(2))q

If in an A.P., S_(2n)=3.S_(n) then S_(3n) : S _(n) = (a)5 (b) 6 (c)7 (d)8

If S_1,S_2,S_3,………….S_n denote the sum of 1,2,3…………n terms of an A.P. having first term a and S_(kx)/S_x is independent of x then S_1+S_2+S_3+……..+S_n= (A) (n(n+1)(2n+1)a)/6 (B) ^(n+2)C_3a (C) ^(n+1)C_3a (D) none of these

If a,b,c be the pth , qth and rth terms of an A.P., then p(b-c) + q(c-a) + r(a-b) equals to :

If A=sqrt((s-a)(s-b)(s-c)) , then express c in terms of A,s,a and b.