In a sequence of (4n + 1) terms the first (2n + 1) terms are in AP whose common difference is 2, and the last (2n + 1) terms are in GP whose common ratio is 0.5. If the middle terms of the AP and GP are equal, then the middle term of the sequence is

In a sequence of (4n+1) terms, the first (2n+1) terms are n A.P. whose common difference is 2, and the last (2n+1) terms are in G.P. whose common ratio is 0.5 if the middle terms of the A.P. and LG.P. are equal ,then the middle terms of the sequence is (n .2 n+1)/(2^(2n)-1) b. (n .2 n+1)/(2^n-1) c. n .2^n d. none of these

In a sequence of 21 terms the first 11 terms are in A.P. with common difference 2. and the last 11 terms are in G.P. with common ratio 2. If the middle tem of the A.P. is equal to the middle term of the G.P., then the middle term of the entire sequence is

In an A.P., if the first term is 22, the common difference is -4 and the sum to n terms is 64, find n .

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 gerneral term of an A.P. is 2n + 5 , then its common difference is

In an A.P., if common difference is 2, sum to n terms is 49, 7th term is 13, then n=

Find the mean of first n terms of an A.P. whose first term is a and common difference is d.

The sum of first n terms of an A.P. is 5n ^(2)+ 4n, its common difference is :

The first four terms of an A.P. whose first term is -2 and the common difference is -2 are