If the coefficients of am and an in the expansion of (1+ a)m + n

Subject

Mathematics

Class

NDA Class 12

Pre Boards

Practice to excel and get familiar with the paper pattern and the type of questions. Check you answers with answer keys provided.

Sample Papers

Download the PDF Sample Papers Free for off line practice and view the Solutions online.
Advertisement

 Multiple Choice QuestionsMultiple Choice Questions

1.

If n  N, then 121n - 25n + 1900n -  - 4n is divisible by which one of the following ?

  • 1904

  • 2000

  • 2002

  • 2006


2.

If n = 2007!, then what is 1log2n + 1log3n + 1log4n + ... + 1log2017n = ?

  • 0

  • 1

  • n2

  • n


3.

In the expansion of (1 + x)43, if the coefficients of (2r + 1)th and (r + 2)th terms are equal, then what is the value of r (r  1) ?

  • 5

  • 14

  • 21

  • 22


4.

What is the principal argument of (- 1 - i), where i =  - 1 ?

  • π4

  • - π4

  •  - 3π4

  • 3π4


Advertisement
5.

Let α and β be real numbers and z be a complex number. If z2 + αz + β = 0 has two distinct non-real roots with Re(z) = 1, then it is necessary that :

  • β   - 1, 0

  • β = 1

  • β  1, 

  • β  0, 1


6.

Let A and B be subsets of X and C = (A  B')  (A'  B), where A' and B' arecomplements of A and B respectively in X. What is C equal to?

  • (A  B') - (A  B')

  • A'  B - A'  B

  • A  B - A  B

  • A'  B' - A'  B' 


7.

How many numbers between 100 and 1000 can beformed with the digits 5, 6, 7, 8, 9, if the repetition of digits is not allowed ?

  • 35

  • 53

  • 120

  • 60


8.

The number of non-zero integral solutions of the equation   1 - 2ix = 5x is :

  • Zero (No solution)

  • One

  • Two

  • Three


Advertisement
9.

If the ratio of AM to GM of two positive numbers a and b is 5 : 3, then a : b is equal to :

  • 3 : 5

  • 2 : 9

  • 9 : 1

  • 5 : 3


Advertisement

10.

If the coefficients of am and an in the expansion of (1+ a)m + n are α and β, then which one of the following is correct ?

  • α = 2β

  • α = β

  • 2α = β

  • α = m + nβ


B.

α = β

1 +xnrthCoefficient Tr +1 = Crnxr1 + am +nGiven, coefficient of am is α and an is βCmm + n = α    ...iCnm + n = β    ...iiOn dividing, we getm + n!n! m!m  n!n! m! = αβα = βOrWe know, Cmm + n = Cnm + nSo, α = β


Advertisement
Advertisement