# How do you determine the period of y= cospix?

$\text{period} = 2$
The period of any cosine function can be found by $T = \frac{2 \pi}{n}$ where $n$ is the same $n$ in the general function $y = a + b \cos \left(n x\right)$
In $y = \cos \left(\pi x\right)$, $n = \pi$
So the period of the function is $T = \frac{2 \pi}{n} = \frac{2 \pi}{\pi} = 2$