# How do you graph  y=3cos(x/2)?

Jul 18, 2018

As below.

#### Explanation:

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

$\text{Given } y = 3 \cos \left(\frac{x}{2}\right)$

$A = 3 , B = \left(\frac{1}{2}\right) , C = D = 0$

Amplitude " = |A| = 3

"Period ' = (2 pi) / |B| = (2 pi) / (1/2) = 4 pi

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

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

graph{3 cos (x / 2) [-10, 10, -5, 5]}