Cyclic functions are mathematical functions that repeat their values in regular intervals. The most common examples are the sine and cosine functions, which are fundamental in trigonometry. These functions have a period of 2\pi, meaning they return to the same value every 2\pi radians. These functions are essential in various fields, including physics, engineering, and signal processing. They help model periodic phenomena, such as sound waves and seasonal changes. Understanding cyclic functions is crucial for analyzing patterns and behaviors that occur in cycles.