Tag: introduction to geometric progression

Questions Related to introduction to geometric progression

Multiple choice maths geometric sequences introduction to geometric progression understanding geometric progressions introduction to geometric progressions

Find the GP whose $5^{th}$ term is $48$ and $9^{th}$ term is$ 768$.

  1. $3,6,12,24$
  2. $2,4,8,16$
  3. $6,12,24,48$
  4. $12,24,36,48$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$\displaystyle { ar }^{ 4 }=48$
$\displaystyle { ar }^{ 8 }=768$
$\displaystyle \therefore \quad { r }^{ 4 }=16$
$\displaystyle \therefore \quad r=2$
$\displaystyle a.{ 2 }^{ 4 }=48$
or, $\displaystyle a=\frac { 48 }{ 16 } =3$
The GP is 3,6, 12,24,.....

Multiple choice maths geometric sequences introduction to geometric progression understanding geometric progressions introduction to geometric progressions

The reciprocals of all the terms of a geometric progression form a ________ progression.

  1. AP

  2. HP

  3. GP

  4. AGP

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Let  $ a $ be the first term  and $ r $ be the common ratio of the GP. 

So, the series is $ a, ar, ar^2... $

Their reciprocals are $ \dfrac {1}{a}, \dfrac {1}{ar}, \dfrac {1}{ar^2} .. $

It is also a GP, with first term $ \dfrac {1}{a} $ and common ratio $ \dfrac {1}{r} $
Multiple choice maths geometric sequences introduction to geometric progression understanding geometric progressions introduction to geometric progressions

In a _______ each term is found by multiplying the previous term by a constant.

  1. arithmetic sequence

  2. geometric series

  3. arithmetic series

  4. harmonic progression

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

geometric series is a series for which the ratio of each two consecutive terms is a constant function of the summation index .

Or,
In a Geometric series each term is found by multiplying the previous term by a constant.
$(Ans \to B)$

Multiple choice maths geometric sequences introduction to geometric progression understanding geometric progressions introduction to geometric progressions

A _________ is a sequence of numbers where each term in the sequence is found by multiplying the previous term with a unchanging number called the common ratio.

  1. geometric progression

  2. arithmetic series

  3. arithmetic progression

  4. harmonic progression

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A geometric progression is a sequence of numbers where each term in the sequence is found by multiplying the previous term with a with a unchanging number called the common ratio.
Example: $2, 6, 18, 54, 108....$
This geometric sequence has a common ratio $3$.

Multiple choice maths geometric sequences introduction to geometric progression understanding geometric progressions introduction to geometric progressions

$10,20,40,80$ is an example of

  1. fibonacci sequence

  2. harmonic sequence

  3. arithmetic sequence

  4. geometric sequence

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$10, 20, 40, 80$ is an example of geometric sequence.
In geometric sequence, the ratio of succeeding term to the preceeding term is always equal.

Here the common ratio is $2$.

Multiple choice maths geometric sequences introduction to geometric progression understanding geometric progressions introduction to geometric progressions

Identify the geometric series.

  1. $1 + 3 + 5 + 7 +....$
  2. $2 + 12 + 72 + 432...$
  3. $2 + 3 + 4 + 5 +...$
  4. $11 + 22 + 33 + 44+...$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Geometric series is of the following form:

$a+ar+ar^2+ar^3 +ar^4+..........+ar^n$
Series $2+12+72+432+......$ follows the same with $a=2$ and $r=6$.
Hence, option B is correct.

Multiple choice maths geometric sequences introduction to geometric progression understanding geometric progressions introduction to geometric progressions

$1, 3, 9, 27, 81$ is a

  1. geometric sequence

  2. arithmetic progression

  3. harmonic sequence

  4. geometric series

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$1, 3, 9, 27, 81$ is a geometric sequence.
A geometric progression is a sequence of numbers such that the quotient of any two successive members of the sequence is a constant called the common ratio of the sequence.