How do you graph #y=2/3cosx# over the interval #0<=x<=360#?
"Graphing" is just plotting calculated values of y for a list of x.
Set up a table with various "x" values. Calculate the corresponding "y" values and then plot them on a graph, or use a spreadsheet or plotting program.
In this case, we know that the cosine function is regular and periodic. One full cycle looks like any other. The "