Mathematics

Find a formula for the general term an of the sequence (starting with a1):
{−3/16,4/25,−5/36,6/49,…}. I'm having problems dealing with the negative signs...


Answers

Czarny333

2 years ago Comment

This is an alternating sequence (minus, plus, minus, plus, etc..). So the general term will have a (-1)^n

−3/16,4/25,−5/36,6/49,…

Why not just remove them? Obviously, there is a factor of "-1" in the final result. Remember that and move on with the rest.

3/16, 4/25, 5/36, 6/49,…

3/4^2 4/5^2 5/6^2 6/7^2

An = (−1)^n * [(n + 2) / (n + 3)^2]