# How do you find the amplitude, period, phase shift for y=cos3x?

Jun 20, 2017

graph{y=cos(3x) [-10, 10, -5, 5]}

#### Explanation:

$y = \cos 3 x$

• AMPLITUDE: $1$
• PERIOD: $\frac{2 \pi}{3}$
• HORIZONTAL SHIFTS: none
• VERTICAL SHIFTS: none
• TYPE: cosine graph

Guide

• AMPLITUDE = distance from middle of graph (y=0) to highest and lowest points on graph
• PERIOD = interval in which the graph repeats itself
period formula for cosine: $\frac{2 \pi}{|} b |$
$b$ is the coefficient of $x$
graph{y=cos(3x) [-10, 10, -5, 5]}