# Sine & Cosine Period Action (1)!

- Author:
- Tim Brzezinski

Recall we've just learned that the sine and cosine functions are said to be

**periodic functions**. Interact with the apps below for a few minutes. Please answer the questions that follow each one.## PARENT SINE FUNCTION

How long is the blue arc (that goes around the circle)? How do you know this to be true?

For the phenomena you observed, what can we conclude about the period of the parent sine function ? How do we know this to be true?

## PARENT COSINE FUNCTION

For the phenomena you observed, what can we conclude about the period of the parent cosine function ? How do we know this to be true?