Question

6, 1, -4, -9,...

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Is this sequence arithmetic or geometric? What's the common difference or common ratio? What is the recursive formula?

Answer 1

Texaschic nailed it when saying that it's arithmetic

The recursive way to write this is to say


`a_1 = 6`

`a_n = a_(n-1) - 5`

which tells us "start at 6 and each time subtract off 5"

The
`a_n` portion is the nth term while
`a_(n-1)` is the term just before the nth term