Question

1.2, 3, 7.5, 18.75, ... Which formula can be used to describe the sequence?

Answer 1

Answer:

The formula is:

$a_n=1.2(\frac{5}{2})^{n-1}$

Step-by-step explanation:

The geometric sequences are those in which the division between the terms $a_{n + 1}$ and $a_n$ of the sequence are equal to a constant common reason called "r"

The geometrics secencias have the following form:

$a_n=a_1(r)^{n-1}$

Where $a_1$ is the first term of the sequence

In this sequence we have the following terms

1.2, 3, 7.5, 18.75

Then notice that:

$\frac{3}{1.2}=\frac{5}{2}\\\\\frac{7.5}{3}=\frac{5}{2}\\\\\frac{18.75}{7.5}=\frac{5}{2}$

Then:

$r=\frac{5}{2}$  and $a_1=1.2$

Finally the formula is:

$a_n=1.2(\frac{5}{2})^{n-1}$

Answer 2

Answer:

Answer: "f(x) = 1.2(2.5)x-1"

Step-by-step explanation: