Multiple Plots

To plot multiple expressions in the same 2D-plot window simply change the highlighted expression in the algebra window, switch to the 2D-plot window and issue a Insert > Plot commandB2C2._ for each expression to be plotted.

A vector of two expressions will be plotted as a parametric plot (see Parametric PlotsParametric_Plots). However, if a vector of three or more expressions is highlighted, the Insert > Plot commandB2C2._ plots each element of the vector.

Use the Author > Vector command.UGCR4 to type in a vector of new expressions. Alternatively, use the Calculus > Vector command.WK1F5 to generate a vector of an expression evaluated at a sequence of points. For example,

VECTOR(x^k, k, 0, 2, 1/4)

simplifies to

⎡ 1/4 1/2 3/4 5/4 3/2 7/4 2⎤
⎣1, x , x , x , x, x , x , x , x ⎦

and plots as a family of curves in the 2D-plot window.

Note that multiple plots all share the same plot scale and range. Therefore, you may have to zoom out and/or move the center of the 2D-plot window to see all of the plot lines simultaneously. Also, you can press the Esc key to stop any subsequent plots from being plotted in the 2D-plot window.

To move a plot line relative to the others, add an offset to the corresponding expression in the algebra window. To magnify or shrink a plot line relative to the others, multiply the corresponding expression by a scaling factor in the algebra window. Sometimes it is advisable both to shift and scale plot lines in order to optimally frame several of them in a single window. Or, instead of individually scaling expressions, expressions may be plotted in multiple plot windows, each with their own scales (see the Window > New 2D-plot Window command1XN1JOT).

To compare coordinate values of multiple plot lines you may want to turn on trace mode using the Options > Trace Plots command1FN.FSI. When you switch on trace mode the cross (displayed as a small box) will move to the plot line of the last expression in the list at the current x-coordinate. You may then use the mouse or right and left arrow keys as described previously to trace along the plot. To trace another plot line use mouse or the up and down arrow keys as follows:

• Up arrow or click the right mouse button and choose Trace previous plot to move the box to the previous expression’s plot line.

• Down arrow or click the right mouse button and choose Trace next plot to move the box to the next expression’s plot line.

In trace mode the number of the expression being traced is displayed in the 2D-plot window title bar. Thus when plotting several expressions, trace mode is a good way to determine the correlation between plot line and expression.

Use the Options > Display > Plot Color commandJDDXSP to customize the colors used for multiple plot lines.

A particular plot line may be deleted by using the Edit > Delete Plot command49KM2E.

Whenever a 2D-plot window changes size, all plots currently contained in that plot window will be recalculated and subsequently replotted.

If it takes too long to regenerate the plots while resizing a plot window using the sizing handles, you can turn off the Show Window Contents While Dragging feature of Windows. When this feature is on, a window’s contents is displayed while it is moved or resized. When this feature is off, only an outline of a window is displayed while it is moved or resized. So, turning this feature off allows the plot window to be resized before any plots are regenerated.

To toggle this feature on or off, run the Window’s Control Panel Display program. If running Windows 98, click on the Effects tab of the dialog box. If running Windows NT or Windows 95 with Microsoft Plus!, click on the Plus! tab. Finally click on the Show Window Contents While Dragging check box to toggle the feature on or off.