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Plotting Functions and Lists

Mathematica maintains separate commands for plotting functions expressed symbolically and expresses as a list. The basic plotting command for plotting functions of one variable is

	Plot[f[x],{x,x_min,x_max},
	     PlotRange->{y_min,y_max},PlotPoints -> 30]
Here we have included two of several options: PlotRange, which controls which portion of the range to display; and PlotPoints, which controls the number of sample points to use when plotting the function. The basic surface plotting command is similar,
	Plot3D[f[x,y],{x,x_min,x_max},{y,y_min,y_max},
		 PlotRange->{z_min,z_max}, PlotPoints -> {30,30}]

The commands to plot lists are similar. To plot a one-dimensional list, use

	ListPlot[mylist,PlotRange->{y_min,y_max},PlotJoined->True]
Notice that we do not have to specify the x range which determines the domain of the plot. Mathematica automatically uses the entire list. PlotRange and PlotJoined are options. The default value for PlotJoined is False, which causes Mathematica to plots points but not connect them. The command to plot a two-dimensional list is
	ListPlot3D[mylist,PlotRange->{z_min,z_max}]

In addition to plotting the graph of a function of two variables, we will also want to be able to plot the contour plot and the density plot of the functions. Including several options, these are:

	ContourPlot[f[x,y],{x,x_min,x_max},{y,y_min,y_max},
		Contours -> 20, ContourShading -> True, 
		PlotPoints-> 30,
		ContourSmoothing -> Automatic]
Contours controls the number of contours, ContourShading shades the plot according to the values of the function, PlotPoints controls the number of sample points in each direction, and ContourSmoothing controls the smoothness of the contours. Similarly, there is a command ListContourPlot which can be used to construct contour plots of two dimensional data sets.
	ListContourPlot[mylist,Contours -> 20, 
		ContourShading -> True,
		ContourSmoothing -> Automatic]
The command for producing a density plot is:
	DensityPlot[f[x,y],{x,x_min,x_max},{y,y_min,y_max},
		Mesh -> False, PlotPoints-> 30]
Mesh determines whether or not the grid lines are shown on the plot. Similarly, there is command ListDensityPlot,
	DensityPlot[mylist,Mesh -> False]




Fri Sep 3 15:13:30 EDT 1999