#### Graphs of Sine and Cosine Functions

- The graph of where -\pi<x<3\pi are plotted below. Do note that it extends beyond the drawn range.

- There are a few observations we can make, and we can tie it back to what we have already learnt:

i) The graph repeats itself after an interval of 2\pi units. We say that the graph has a period of 2\pi, and hence is called a periodic function. Previously, we have learnt that \sin(x+2\pi).