Determining a Sequence Given a Recursive Formula

Which sequence could be partially defined by the recursive formula [tex]f(n+1)=f(n)+2.5[/tex] for [tex]n \geq 1[/tex]?



Answer :

To determine a sequence defined by the recursive formula [tex]\( f(n+1) = f(n) + 2.5 \)[/tex] for [tex]\( n \geq 1 \)[/tex], we need to start with an initial term and then apply the given formula iteratively to generate subsequent terms.

Let's assume the initial term of the sequence is [tex]\( f(1) = 0 \)[/tex].

Using the recursive formula, we'll compute the next few terms step-by-step:

1. First term:
[tex]\[ f(1) = 0 \][/tex]

2. Second term:
[tex]\[ f(2) = f(1) + 2.5 = 0 + 2.5 = 2.5 \][/tex]

3. Third term:
[tex]\[ f(3) = f(2) + 2.5 = 2.5 + 2.5 = 5.0 \][/tex]

4. Fourth term:
[tex]\[ f(4) = f(3) + 2.5 = 5.0 + 2.5 = 7.5 \][/tex]

5. Fifth term:
[tex]\[ f(5) = f(4) + 2.5 = 7.5 + 2.5 = 10.0 \][/tex]

6. Sixth term:
[tex]\[ f(6) = f(5) + 2.5 = 10.0 + 2.5 = 12.5 \][/tex]

7. Seventh term:
[tex]\[ f(7) = f(6) + 2.5 = 12.5 + 2.5 = 15.0 \][/tex]

8. Eighth term:
[tex]\[ f(8) = f(7) + 2.5 = 15.0 + 2.5 = 17.5 \][/tex]

9. Ninth term:
[tex]\[ f(9) = f(8) + 2.5 = 17.5 + 2.5 = 20.0 \][/tex]

10. Tenth term:
[tex]\[ f(10) = f(9) + 2.5 = 20.0 + 2.5 = 22.5 \][/tex]

So, the first 10 terms of the sequence defined by the recursive formula [tex]\( f(n+1) = f(n) + 2.5 \)[/tex] starting with [tex]\( f(1) = 0 \)[/tex] are:

[tex]\[ 0, 2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 17.5, 20.0, 22.5 \][/tex]