If `A_1, A_2, G_1, G_2, ; a n dH_1, H_2` are two arithmetic, geometric and harmonic means respectively, between two quantities `aa n db ,t h e na b` is equal to `A_1H_2` b. `A_2H_1` c. `G_1G_2` d. none of these

Let A;G;H be the arithmetic; geometric and harmonic means of two positive no.a and b then A>=G>=H

If A_(1) , A_(2) , A_(3) , G_(1) , G_(2) , G_(3) , and H_(1) , H_(2) , H_(3) are the three arithmetic, geometric and harmonic means between two positive numbers a and b(a gt b) , then which of the following is/are true ?

If A_(1),A_(2),A_(3);G_(1),G_(2),G_(3); and H_(1),H_(2),H_(3) are the three arithmetic,geometric and harmonic means between two positive numbers a and b(a>b), then which of the following is (are) true?

If m ,n in Na n dm^2-n^2=13 ,t h e n(m+1)(n+1) is equal to a. 42 b. 56 c. 50 d. none of these