# How do you find the amplitude and period of y=-2cos(4t)?

Apr 21, 2018

#### Explanation:

show the explanition

$y = a \cdot \cos \left(w t\right)$

the amplitude is

$a = - 2 m$

$w = 2 \pi f$

$f = \frac{1}{t}$

$w = \frac{2 \pi}{t}$

$t = \frac{2 \pi}{w}$

$t = \frac{2 \pi}{4} = \frac{\pi}{2} = 1.571 s$