Question

Write an explicit and recursive formula for the sequence -4, -6, -8, 10

Answer 1

Each term is 2 greater than the term before it. Thus for any given term, an, our equation is:

an=2n

We can write this in a form closer to standard, by noting that a1=2, so we can make it dependent on a1..

an=a1+2(n−1)=2+2(n−1)