Question

Which of the following are examples of a geometric sequence? Select any and all that apply: may be more than one correct answer.

Answer 1

Answer:

( 1 , -2 , 4 , -8 , 16 , ... )

( 9 , 3 , 1 , 1/3 , 1/9 , ... )

Step-by-step explanation:

A geometric sequence has a common ratio in consecutive terms,

In sequence,

$1, \frac{1}{2}, \frac{1}{6},\frac{1}{24},\frac{1}{120}.....$

$\frac{1/2}{1}\neq \frac{1/6}{1/2}\neq \frac{1/24}{1/6}\neq \frac{1/120}{1/24}...$

i.e.

$1, \frac{1}{2}, \frac{1}{6},\frac{1}{24},\frac{1}{120}.....$ is not a Geometric sequence,

1 , -2 , 3 , -4 , 5 , ...

$\frac{-2}{1}\neq \frac{3}{-2}\neq \frac{-4}{3}\neq \frac{5}{-4}...$

i.e. 1 , -2 , 3 , -4 , 5 , ... is not a Geometric sequence,

In sequence,

1 , -2 , 4 , -8 , 16 , ...

$\frac{-2}{1}=\frac{4}{-2}= \frac{-8}{4}= \frac{16}{-8}...$

i.e. 1 , -2 , 4 , -8 , 16 , .... is a Geometric sequence,

In sequence,

0 , 1 , 0 , -1 , 0 , .....

$\frac{1}{0}\neq \frac{0}{1}\neq \frac{-1}{0}\neq \frac{0}{-1}...$

i.e. 0 , 1 , 0 , -1 , 0 , .....is not a Geometric sequence,

In sequence,

9 , 3 , 1 , 1/3 , 1/9 , ...

$\frac{3}{9}=\frac{1}{3}= \frac{1/3}{1}= \frac{1/9}{1/3}...$

i.e.  9 , 3 , 1 , 1/3 , 1/9 , ... is a Geometric sequence,

In sequence,

1 , 3 , 5 , 7 , 9 , ...

$\frac{3}{1}\neq \frac{5}{3}\neq \frac{7}{5}\neq \frac{9}{7}...$

i.e. 1 , 3 , 5 , 7 , 9 , ... is not a Geometric sequence