[" Q13.If the variance of the terms in an "],[" increasing A.P."b_(1),b_(2),b_(3),....,b_(11)" is "90" ,"],[" then the common difference of this "],[" A.P.is "]

If a,b,c are in G.P and a,p,q are in A.P such that 2a, b+p, c +q are in G.P ., then the common difference of A.P is

If for each n in N, S_(n)=nA+(1)/(2)n(n+1) B is sum of the first n terms of an A.P., the common difference of the A.P. is

If a. b, c are in G.P. and log_ca , log_b c , log_a b are in AP show that the common difference of the AP is 1(1/2)

11, 7, 3, -1 is an A.P. whose first term is 11 and the common difference is equal to 7-11=4.

If a^2,b^2,c^2 are in A.P., then the terms given below are also in A.P. a/(b+c),b/(c+a),c/(a+b) .

We know that, if a_1, a_2, ..., a_n are in H.P. then 1/a_1,1/a_2,.....,1/a_n are in A.P. and vice versa. If a_1, a_2, ..., a_n are in A.P. with common difference d, then for any b (>0), the numbers b^(a_1),b^(a_2),b^9a_3),........,b^(a_n) are in G.P. with common ratio b^d. If a_1, a_2, ..., a_n are positive and in G.P. with common ration, then for any base b (b> 0), log_b a_1 , log_b a_2,...., log_b a_n are in A.P. with common difference logor.If x, y, z are respectively the pth, qth and the rth terms of an A.P., as well as of a G.P., then x^(z-x),z^(x-y) is equal to

If a^2,b^2,c^2 are in A.P., then the terms given below are also in A.P. 1/(b+c),1/(c+a),1/(a+b) .

If the first term of an A.P. is a and n t h term is b , then its common difference is