first off , do you know how to sketch the graph of cos 1/2 Θ ?
Note that its period is 2π/(1/2)=4π
The usual graph we draw (cos Θ) has a period of 2π but this time , 4π .
|cos 1/2 Θ| - reflect the negative part of the graph to the postive side
- |cos 1/2 Θ| - reflect the whole graph about the x-axis
2 - |cos 1/2 Θ| - shift the graph up by 2 units .