ECAT Pre Engineering MCQ Test With Answer for Chapter 8 Mathematics

Sum of n terms of a geometric series if | r | < 1 is

• 
  A
• 
  B
• 
  C
• 
  D

If a₁, r are first term and the common ratio respectively then the sum of an infinite geometric series is

• 
  A
• 
  B
• 
  C
• 
  D

The formula an = arn-1represents

• nth term of G.P A
• Sum of the first n terms B
• G.M between a and b C
• None of these D

The sum of indicated terms of a sequence is called

• Arithmetic series A
• Series B
• Harmonic series C
• None of these D

The numbers of G₁, G₂, G₃...... G_nare called n geometric means between a and b is a, G₁, G_2,G₃, ... G_n, b are in

• H.P. A
• A.P. B
• G.P. C
• None of these D

An indicated sum of terms of a sequence is represented by

• Sn A
• an B
• S(n) C
• {Sn} D

Sum of first n terms of an arithmetic series is

• 
  A
• 
  B
• 
  C
• 
  D

The sum of first twenty odd integers in A.P is

• 400 A
• 397 B
• 404 C
• 408 D

A number H is said to be the H.M. between a and b if a, H, b are in

• A.P. A
• G. P. B
• H. P. C
• None of these D

• A.P. A
• G.P. B
• H.P. C
• None of these D

A,G,H are in

• A.P A
• G.P B
• H.P C
• None of these D

The5thand 13th terms of an A.P are 5 and-3 respectively The first term of the A.P is

• 1 A
• -15 B
• 9 C
• 2 D

The A.M. of two numbers is 34 and G.M. is 16, the numbers are

• 2 and 64 A
• 64 and 3 B
• 64 and 4 C
• None of these D

Three consecutive terms of a progression are 30, 24, 20. The next terms of the progression is

• 
  A
• 
  B
• 
  C
• 
  D

An infinite arithmetic series is always

• Convergent A
• Oscillatory B
• Divergent C
• None of these D

-2, 1, 4, 7,.... is ______

• Harmonic sequence A
• Arithmetic sequence B
• Geometric sequence C
• Arithmetic series D

The nth term of a G.P. is

• a₁rⁿ A
• a₁rⁿ⁺¹ B
• a₁r^n-1 C
• a₁r^-n D

The sum of first 60 natural numbers is

• 1830 A
• 3660 B
• 1640 C
• 1770 D

The sum of an infinite geometric series exist if

• | r | < 1 A
• | r | > 1 B
• r = 1 C
• r = -1 D

An infinite sequence has no

• nth term A
• Last term B
• Sum C
• None of these D

An A.P., a G.P. and a H.P. have the same first and last terms and the same odd numbers of terms, the middle terms of the three series are in

• A.P. A
• G.P. B
• H.P. C
• None of these D

For an A.P common difference d

• Can be zero A
• May or may not zero B
• Cannot be zero C
• None of these D

• 2²- n - 1 A
• 1 - 2^-n B
• n + 2^-n-1 C
• 2ⁿ- 1 D

Write the first four terms of the sequence if a_n= (-1)ⁿn²

• -1, 4, -9, 16 A
• 1, -4, 9, 16 B
• 1, 4, 9, 16 C
• None of these D

A sequence of number whose reciprocals form an arithmetic sequence is called

• Geometric sequence A
• Arithmetic series B
• Harmonic sequence C
• Harmonic series D

A number A is said to be the A.M between the two numbers a and b if a, A, b are in

• A.M A
• A.P B
• G.P C
• G.M D

If a₁and r are the first term and the common ratio respectively then (n + 1)th term of the G.P. is

• 0 A
• a₁r^n-1 B
• a₁rⁿ⁺¹ C
• a₁rⁿ D

Let S_ndenote the sum of the first n terms of an A.P. If S_2n= 3 S_n: S_nis equal to

• 4 A
• 6 B
• 8 C
• 10 D

Given two numbers a and b. Let A denote the single A.M. between these and S denote the sum of n A.M.'s between them. Then S/A depends upon

• n, a, b A
• n, a B
• n, b C
• n D

If p, q, r and in A.P., a is G.M. between p and q and b is G.M. between q and r, then a², q², b²are in

• A.P. A
• G.P. B
• H.P. C
• None of these D