GUESS THE PERIODIC SIGNAL
1. $ x(t)\! $ is an $ odd\! $ function.
2. $ x(t)\! $ has a fundamental period of $ T = 9\! $
3. The Pk-Pk of the function is 10.
4. The function is offset by a value of +1
5. Finally, $ a_{0} = 1\! $
ANSWER
$ x(t) = 5cos(\frac{2\pi}{9}t)+1\! $