Question

The table below represents a geometric sequence.

Answer 1

Answer:

B. f(1)=4

$f(n)=5\cdot f(n-1)$, $n\ge2$

Step-by-step explanation:

From the table the first term of the geometric sequence is:

$f(1)=4$

We can use the first term and the second term to determine the common rtaio.

The common ratio is

$r=\frac{20}{4}=5$

Note that, we could have also used the 3rd and second term to find the common ratio.

The recursive formula is given by:

$f(n)=r\cdot f(n-1)$

We plug in the common ratio to get:

$f(n)=5\cdot f(n-1)$