Thread: Sequence A-Level Question

Find the nth tern of the sequence
-3,5,-7,9

Originally Posted by helpishere

Find the nth tern of the sequence
-3,5,-7,9

First ignore the negatives.

It's easy to see that the n-th term is then given by

Now we see that every odd term ( , , etc.) is negative.

So all we do is multiply the expression by where is the term. So if it's and odd term, it will have a negative value and a positive value for an even term.