ECAT Pre Engineering Mathematic MCQ Test With Answer for Chapter 8 (Sequences and Series)

If a, b, c are in A.P., then 3^a, 3^b, 3^care in

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

If #n = (n-5)2 + 5, then find #3 x #4.

• 54 A
• 12 B
• 4 C
• 9 D

A,G,H are in

• A.P A
• G.P B
• H.P 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

Find the geometric mean between 4 and 16

• 
  A
• 
  B
• 
  C
• 
  D

If a_n= 2n -3, write the first four terms

• -3, -1, 1, 3 A
• 1, 3, 5, 7 B
• -1, 1, 3, 5 C
• None of these D

If b₁, b₂, b₃, ... are in G.P. with first term unity and common ratio r, then the minimum value of b₁- b₃+ b₅is equal to

• 3/4 A
• 1/4 B
• 1 C
• None of these D

H₁, H₂, H₃, .... H_nare called n harmonic means between a and b if a, H₁, H₂, H₃, ... H_nb are in

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

The sum of an indicated number of terms in a sequence is called

• sequence A
• progression B
• Series C
• Mean D

• 1 A
• 2 B
• 3/2 C
• 5/2 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

A function whose domain is a subset of natural numbers is called ______

• Identity function A
• Sequence B
• Onto function C
• Series D

The difference of two consecutive terms of an A.P. is called ______

• General term A
• Common ratio B
• Common difference C
• None of these D

Sum of first n terms of an arithmetic series is

• 
  A
• 
  B
• 
  C
• 
  D

if a_{9 =19,a9=31 are the 6th and 9th term of an A.P. and d=4 is the common difference, then 18th term of the sequence is}

• 65 A
• 67 B
• 71 C
• 75 D

99th term of the series 2 + 7 + 14 + 23 + 34 + ..... is

• 9998 A
• 9999 B
• 10000 C
• None of these D

An infinite sequence has no

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

The series obtained by adding the terms of an arithmetic sequence is called the

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

The nth term of an A.P., is 12-4n. Its common difference is

• 8 A
• 4 B
• 4 C
• 16 D

An indicated sum of terms of a sequence is represented by

• Sn A
• an B
• S(n) C
• {Sn} D

H.M. between 3 and 7 is

• 
  A
• 
  B
• 
  C
• 
  D

• 2 A
• -3/2 B
• 1 C
• 0 D

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

an - an-1 will be common difference in an A.P if

• n = 1∀n∈ N A
• n>1∧n∈N B
• n∈Z C
• None of the above 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

The formula an = a +(n-1)d for an A.P is called

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

A number A is called the arithmetic mean between a and b if a, A, b is ______

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

If 6th term of a series in A.P, is -2 and 8th term is -8, the first term of the serie is

• 13 A
• -13 B
• 18 C
• -10 D