#### Answer

Please see below.

#### Work Step by Step

The red graph is the graph of $y=-3.5 \cos (\pi x-\frac{\pi }{6})$, and the blue graph is the graph of $y=-3.5 \sec (\pi x-\frac{\pi }{6})$.
The period of both functions are the same and equal $\frac{2\pi }{\pi }=2$.