Answer
amplitude: $4$
period: $\pi$
Work Step by Step
If a function has form $y=A\cos(\omega x)$, then there $|A|$ stands for the amplitude.
First we identify $\omega$ and $A$ from the form of $y=A\cos{(\omega x)}$. 0
Hence, $A=|-4|=4$, $\omega=2.$
To get the period $T$ we can use the formula $T=\frac{2\pi}{\omega}$ to obtain
$T=\frac{2\pi}{2}=\pi$
