Answer:
8π
Explanation:
The period of a periodic function is the minimum amount by which the graph must be shifted right or left to map the graph to itself. Often it can be found by looking at the x-value differences of peaks or other identifiable features of the graph.
Here, there are peaks at x = -6π and x = 2π. The difference between these values is ...
2π -(-6π) = 8π . . . . the period of the graph
__
Additional comment
We note that there is a rising midline crossing at x=0, and another one at x=8π. This confirms the notion that the period is 8π.