If an A.P., a G.P. and a H.P. have the same first term and same `(2n+1)` th term and their `(n+1)^n` terms are a,b,c respectively, then the radius of the circle. `x^2+y^2+2bx+2ky+ac=0` is

an A.P. a G.P. and a H.P. have the same first term & the same last term and the same odd numberof terms . Middle terms of 3 series are in

If the first and (2n-1)^(th) terms of an A.P, a G.P and an H.P of positive terms are equal and their (n+1)^(th) terms are a, b & c respectively then

An A.P., and a H.P. have the same first and last terms and the same odd number of terms. The middle terms of the three series are in

An A.P. and a G.P. of positive terms have the same first term and the sum of their first, second and third terms are respectively, 1, 1/2 and 2. Show that the sum of their fourth terms is 19/2

Let an A.P. a G.P. and a H.P. of positive terms have the same first term a, the same last term b and the same numberof terms (2n+1). Let x,y,z be the (n+1)th terms respectively of the A.P., G.P. and H.P. respectively. On the basis of above information anwer the following question: x,y,z are in (A) A.P. (B) G.P. (C) H.P. (D) none of these

The nth term of an A.P. is 4n -1 . Write down the first 4 terms and the 18 th term of the A.P..

For an A.P., show that (m +n)th term + (m-n) term =2 xx m th term

If the sum of first n terms of an A.P. is 3n^2 + 2n , find its r^(th) term.

If the first and the nth terms of a G.P., are a and b respectively, and if P is the product of the first n terms. prove that P^2=(a b)^n

If the first and the nth terms of a GP are a and b respectively and if P is the product of the first n terms, then P^(2) is equal to