if x = 1 + 2 + 4/2! + 8/3! + 16/4! + ...., then x-1 is equal to
e-2
e2
e1/2
None of these
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 S is the sum of an infinite GP, the first term a, then the common ratio r is given by
is equal to
n
1/n
1/2 (n+n-1)
1/2 (en + e-n)
The sum to infinity of the progression 9 - 3 + 1 -1/3 + .... is
9
9/2
27/4
15/2
The arithmetic means of first n odd natural number is
n2
2 n
3 n
The 5th term of the series is
1/3
1
2/5
The sum of the integers from 1 to 100 which are divisible by 3 and 5 is
2317
2632
315
2489
Fifth term of a GP is 2, then the product of its 9 terms is
256
512
1024
1100
In an AP the sum of any two terms, such that the distance of one of them from the beginning is same as that of the other from the end, is
first term
sum of first and last terms
last term
half of the sum of the series