- #1
songoku
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Homework Statement
Find the formula for nth term of:
... , -450 , -270 , -180 , -90 , 90 , 180 , 270 , 450 , ...
Homework Equations
Arithmetic and geometric series
Recursive
The Attempt at a Solution
Usually when finding the formula of Un, n starts from 1. But since the pattern goes infinite in both ways, how can we set which one is the first term?
As for recursive, it usually involves the preceding term, Un-1. Again, how can we determine the preceding term for the above case?
Please give me idea how to start solving this. Thank you very much