# How do you find the amplitude and period of y=4cos(3/4theta)?

May 31, 2018

As below

#### Explanation:

Standard form of the cosine function is

$y = A \cos \left(B x - C\right) + D$

Given : $y = 4 \cos \left(\left(\frac{3}{4}\right) \theta\right)$

$A m p l i t u \mathrm{de} = | A | = 4$

Period $= \frac{2 \pi}{|} B | = \frac{2 \pi}{\frac{3}{4}} = \frac{8 \pi}{3}$

Phase Shift $= - \frac{C}{B} = 0$, no Shift

Vertical Shift $= D = 0$, no Shift