## Calculus 8th Edition

To graph the following function, we will first determine its parent function and then stretch the whole graph step by step. The parent function of $y=|cos(\pi x)|$ is $y=cosx$ (Black dotted line graph in the image). Now, lets transform it a little and graph: $y=cos(\pi x)$, which means shrinking the parent graph horizontally by the factor of $\pi$ (Red line graph in the image) Finally, we graph: $y=|cos(\pi x)|$, which means that we will reflect the portion of the graph below the x-axis about the x-axis (Blue line graph in the image).