## Geometry and Trigonometry## Trigonometry |

## What is a periodic function? |

Periodic functions are those that repeat the same values at regular intervals. For trigonometric functions, the *period* (or the interval of repeated values) is 360 degrees or 2π for the sin, cosine, secant, and cosecant; and 180 degrees or π radians for the cotangent and tangent. (For example, this is often said as “the tangent function has period π.”)