Answer
See below.
Work Step by Step
1. We can find the period of $y=3cos(\pi x)$ as $p=\frac{2\pi}{\pi}=2$. To have the graph include at least 2 periods of the function, set the x-scale so that its width is greater than 4.
2. The amplitude of the function is $3$ and the curve will oscillate in $[-3,3]$, thus we can set the y-scale to be greater than this range.
