# How do you graph y = -2 cos 3x?

Nov 1, 2015

A general cosine graph of form $y = A \sin B x$ has amplitude A which represents the maximum displacement from the rest position, and period $T = \frac{2 \pi}{B}$ which represents the length on the x axis for 1 complete cycle.

So in this case $A = 2 \mathmr{and} T = \frac{2 \pi}{3}$

Hence the graph is drawn as follows :

graph{-2*cos(3x) [-5.55, 5.55, -2.775, 2.774]}