Tag: introduction to sequences and series

Questions Related to introduction to sequences and series

A _____ is a sum of numbers.

  1. sequence

  2. series

  3. term

  4. constant


Correct Option: B
Explanation:

A series is a sum of numbers.

For example:
$1+3+9+27+....$

What is series?

  1. adding all the numbers

  2. subtracting all the numbers

  3. multiplying all the numbers

  4. dividing all the numbers


Correct Option: A
Explanation:

Series is adding all the numbers or sum of all numbers.

For example: $2+4+6+8+10+....$
This is an AP series with common difference $d=2$.

Which one of the following is not a series?

  1. adding first $n$ natural numbers

  2. multiplying first $10$ odd numbers

  3. adding first $20$ even numbers

  4. adding last $20$ natural numbers


Correct Option: B
Explanation:

A series is the sum of some set of terms of a sequence.
So, multiplying first $10$ odd numbers is not a series.

As it will be equal to $1\times 3\times 5\times 7\times 9....$

$\displaystyle \frac{1}{2}+\frac{1}{4}+\frac{1}{6}+\frac{1}{8}+....$ is a

  1. sequence

  2. series

  3. term

  4. constant


Correct Option: B
Explanation:

$\displaystyle \frac{1}{2}+\frac{1}{4}+\frac{1}{6}+\frac{1}{8}+....$ is a series.

As it shows addition.

Adding and constant difference between the terms is called

  1. sequence

  2. constant

  3. term

  4. series


Correct Option: D
Explanation:

Adding and constant difference between the terms is called series.
Example: $1 + 3 + 5 + 7 +... $
Here the common difference is $2$, adding the terms is called series.

A ______ is the sum of some set of terms of a sequence.

  1. term

  2. constant

  3. series

  4. sequence


Correct Option: C
Explanation:

A series is the sum of some set of terms of a sequence.

For example: 
$2,4,6,8,10,....$
Here it is an series of an A.P. with common difference $d=2$.

Expansion of series: $\displaystyle\sum _{n=0}^4 2n$

  1. $0+2+4+8+16$

  2. $0+2+4+6+8$

  3. $2+4+6+8+10$

  4. None of the above


Correct Option: B
Explanation:

Given:  $\displaystyle\sum _{n=0}^{4} 2n$

At n=0: $2n=2 \times 0=0$
At n=1: $2n=2 \times 1=2$
At n=2: $2n=2 \times 2=4$
At n=3: $2n=2 \times 3=6$
At n=4: $2n=2 \times 4=8$
$\therefore 0+2+4+6+8$

Which of the following is not an example of a series?

  1. $1,2,3,4,5,6,...$

  2. $-2,0,2,4,6,8,...$

  3. $1,1,2,3,5,8,..$

  4. None of the above


Correct Option: D
Explanation:

$(A)$ $1,2,3,4,5,6,....$

This is a arithmetic series with common difference $d=1$

$(B)$ $-2,0,2,4,6,8,...$
This is a arithmetic series with common difference $d=2$

$(C)$ $1,1,2,3,5,8,...$
This is a Fibonacci series in which successive terms is determined by sum of 2 preceding terms.
$a _n=a _{n-1}+a _{n-2}$

Ans: None of the above

A fibonacci series is:

  1. series of numbers in which each number (Fibonacci number) is the sum of the two preceding numbers.

  2. the simplest is the series $1, 1, 2, 3, 5, 8,$ etc.

  3. Both are correct

  4. None is correct


Correct Option: C
Explanation:
Sol: A Fibonacci series of numbers is in which each number is the sum of the two preceding numbers examples,
$1,1,2,3,5,8$----------

Which of the following is not a series?

  1. AP

  2. GP

  3. Fibonacci pattern

  4. None of the above


Correct Option: D
Explanation:

Arithmetic progression, Geometric progression and Fibonacci pattern are all series.