If a, b and c are in arithmetic progression, then the roots of the equation ax - 2bx + c = 0 are
Let the coefficients of powers of x in the 2nd, 3rd and 4th terms in the expansion of (1 + x)n, where n is a positive integer, be in arithmetic progression. Then, the sum of the coefficients of odd powers of x in the expansion is
32
64
128
256
The sum 1 x 1! + 2 x 2! + ... + 50 x 50! equals
51!
51! + 1
51! + 1
2 51!
B.
51! + 1
1 x 1! + 2 x 2! + ... + 50 x 50!
= (2 - 1)1! + (3 - 1)2! + (4 - 1)3! + ... + (51 - 1)50!
= (2! - 1!) + (3! - 2!) + (4! - 3!) + ... + (51! - 50!)
= 51! - 1!
= 51! - 1
Six numbers are in AP such that their sum is 3. The first term is 4 times the third term. Then, the fifth term is
- 15
- 3
9
- 4
Let a, b, c, p, q and r be positive real numbers such that a, band c are in GP and ap = bq = cr . Then,
p, q, r are in GP
p, q, r are in AP
p, q, r are in HP
p2, q2, r2 are in AP
Let Sk be the sum of an infinite GP series whose first term is k and common ratio is (k > 0). Then, the value of is equal to
1 -
1 -