Answer:
An equivalent answer would be
The first term is
n is a positive integer.
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Further Explanation:
The sequence is
4, 8, 12, 16, 20
Each time we need a new term, add on 4
eg: 8+4 = 12
The
To find this nth term, we add 4 to the previous term just before the nth term. That previous term being
This is how we can describe the recursive form in words
nth term = (term just before nth term) + 4
Some textbooks will use this type of notation
a(n) = a(n-1)+4
where a(n) is the nth term and a(n-1) is the term just before the nth term.
Now we could re-index things to say
aka
a(n+1) = a(n)+4
and it means "to find the (n+1)th term, add 4 to the nth term".
So it's up to you which format you prefer better.
Keep in mind that a(n) and a(n-1) and a(n+1) are function notation, and NOT multiplication. We can't use the distribution rule here.