Question

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

Answer 1

A general cosine graph of form `y=AsinBx` has amplitude A which represents the maximum displacement from the rest position, and period `T=(2pi)/B` which represents the length on the x axis for 1 complete cycle.

So in this case `A=2 and T=(2pi)/3`

Hence the graph is drawn as follows :

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