Writeanequationtodescribethesequencebelow.Usentorepresentthepositionofaterminthesequence,wheren = 1forthefirstterm.

8 , 24 , 72 , ...

Write your answer using decimals and integers.

an =
(
)n - 1

1 answer

To find the equation that describes the given sequence \(8, 24, 72, \ldots\), we can begin by examining the pattern in the sequence.

  1. Identify the ratio between terms:
    • \( \frac{24}{8} = 3 \)
    • \( \frac{72}{24} = 3 \)

This indicates that each term is multiplied by 3 to get the next term.

  1. Express the terms:
    • The first term \(a_1 = 8\)
    • The second term \(a_2 = 8 \times 3 = 24\)
    • The third term \(a_3 = 8 \times 3^2 = 72\)

Since each term can be expressed as an initial term multiplied by \(3\) raised to a power, we can express the \(n\)-th term of the sequence as follows:

\[ a_n = 8 \times 3^{n-1} \]

Thus, the equation for the \(n\)-th term in the sequence is:

\[ a_n = 8 \times 3^{n-1} \]