Write a recursive formula for an ​, the nth term of the sequence 8,2,−4,−10,...(1 point)

1 answer

To find a recursive formula for the sequence \(a_n\) represented by the terms \(8, 2, -4, -10, \ldots\), we first need to observe the pattern in the sequence.

  1. The first term is \(a_1 = 8\).
  2. The second term is \(a_2 = 2\).
  3. The third term is \(a_3 = -4\).
  4. The fourth term is \(a_4 = -10\).

Next, let's calculate the differences between consecutive terms:

  • \(a_2 - a_1 = 2 - 8 = -6\)
  • \(a_3 - a_2 = -4 - 2 = -6\)
  • \(a_4 - a_3 = -10 - (-4) = -6\)

We can see that each term is obtained by subtracting \(6\) from the previous term. Therefore, we can express the recursive relationship as follows:

\[ a_n = a_{n-1} - 6 \quad \text{for } n \geq 2 \]

We also need to provide the initial condition:

\[ a_1 = 8 \]

Thus, the complete recursive formula for the sequence is:

\[ \begin{align*} a_1 & = 8 \ a_n & = a_{n-1} - 6 \quad \text{for } n \geq 2 \end{align*} \]