# How do you use transformation to graph the cosine function and determine the amplitude and period of y=cos(-1/4x)?

Jul 16, 2018

As below

#### Explanation:

Standard form of a cosine function is $y = A \cos \left(B x - C\right) + D$

$\text{Given : } y = \cos \left(- \frac{x}{4}\right)$

$A = 1 , B = - \left(\frac{1}{4}\right) , C = D = 0$

"Amplitude ' = |A| = 1

$\text{Period } = \frac{2 \pi}{|} B | = \frac{2 \pi}{|} - \frac{1}{4} | = 8 \pi$

$\text{Phase Shift } = - \frac{C}{B} = 0$

$\text{Vertical Shift } = D = 0$