If three numbers a,b,c are in harmonic progression, then which of the following is true?
1/a, b, 1/c are in AP
1/bc, 1/ca, 1/ab are in HP
ab, bc, ca are in HP
a/b, b/c, c/a are in HP
The value of 91/3 × 91/9 × 91/27 × ...... is
9
3
1
None of these
The sum to infinity of the progression 9 - 3 + 1 -1/3 + .... is
9/2
27/4
15/2
The value of is
log 3
log 2
1/2
If a, b, c be in arithmetic progression, then the value of (a+2 b - c) (2 b + c - a) (a + 2 b + c) is
16 a b c
4 a b c
8 a b c
3 a b c
If 2/3, k, 5/8 are in AP, then value of K is
15
21
12
31/48
is equal to
n
1/n
1/2 (n+n-1)
1/2 (en + e-n)
Geometric mean of 7,72,73,....7n is
7
7n/2
7n
Let a be a positive number such that the arithmetic mean of a and 2 exceeds their geometric mean by 1. Then, the value of a is
5
8
If S is the sum of an infinite GP, the first term a, then the common ratio r is given by
