The sum of the series 1 + 1/2 + 1/22 + .......... is __________.
1
1/2
2
None of these
The sum of the squares of first n natural numbers is _______.
The sum to n terms of 1, 8, 27, 64, ........ is ______.
The harmonic mean between a and b is _________.
2ac / ( a + c )
( a + b ) / 2ab
√ab
( a + b ) / ab
The common difference of the A.P 13, 8, 3, -2, ....... is ______.
5
-5
10
-4
If a, b, c are in G.P, then a/b = ?
b/c
b/a
a/c
c/a
The 7th term of 1/3, 1/7, 1/11, ........... is ____________.
27
0
7/3
1/27
If a, b, c are in G. P, then which of the following is true?
a = bc
b2 = ac
c = ab
a2 = bc
The nth term of the series -3 + 6 - 12 + 24 - 48 .......... is _________.
( -1 )n * 3 * 2n-1
1n * 3 * 2n-1
3 * 2n+1
2 * 3n-1
Sum of cubes of first n natural numbers is _______.