Question

Write a recursive formula for the arithmetic sequence:

7,4,1,-2

Answer 1

N - 3

Explanation:

It is a series of -3 so:

7 -3 = 4

4 - 3 = 1

1 - 3 = -2

So:

N-3

where N is the present value in the sequence.

Answer 2

a1 = 7
a(sub)n = a(sub)n-1 - 3

(sub) indicates the values touching the parenthesis are written as a subscript.

The above would be the recursive formula as you are taking the previous number and subtracting 3 to get the next number in the sequence.