Writeanequationtodescribethesequencebelow.Usentorepresentthepositionofaterminthesequence,wheren = 1forthefirstterm.

3 , 12 , 48 , ...

Write your answer using decimals and integers.

an =
(
)n - 1

1 answer

To derive an equation for the given sequence: \(3, 12, 48, ...\), we first observe how the sequence progresses.

  1. Let's list out the terms with their positions:

    • \(a_1 = 3\)
    • \(a_2 = 12\)
    • \(a_3 = 48\)
  2. Next, let's examine the pattern:

    • From \(a_1\) to \(a_2\): \(12 = 3 \times 4\)
    • From \(a_2\) to \(a_3\): \(48 = 12 \times 4\)

We see a multiplication pattern. Each term seems to be multiplied by 4 to get the next term.

  1. To represent this as a formula, we can see that:
    • The first term is \(3\).
    • Each subsequent term is multiplied by \(4\) based on the previous term.

The \(n\)-th term of the sequence can be formulated as: \[ a_n = 3 \times 4^{n-1} \]

So the equation to describe the sequence is: \[ a_n = 3 \cdot 4^{n-1} \]