Answer:
Check below, please
Explanation:
Periodic phenomena such as temperature, tides, are easy to fit in periodic trigonometric functions likes because these events have cycle, period, so it is easier to model trigonometric functions which already describe a frequency, a period etc. Since you know what makes an event a periodic one.
The main difficulty lies on how to restrict the Domain of these functions, and dealing with infinity values, and how to distinguish on modelling the subtle differences between some periodic functions, like sine, and cosine.
The other one, but not as hard is to recognize it from scatter plots periodic curves and to distinguish them.