Answer
amplitude: $\frac{9}{5}$
period: $\frac{4}{3}$
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 $y=A{(\cos\omega x)}$.
Hence, $A=\left|\frac{9}{5}\right|=\frac{9}{5}$, $\omega=\frac{-3\pi}{2}.$
To get the period $T$ we can use the formula $T=\left|\frac{2\pi}{\omega}\right|$ to obtain
$T=\left|\dfrac{2\pi}{\frac{-3\pi}{2}}\right|=\dfrac{4}{3}$
