Indirectly, building your equation outside the plot window

Plot Matrices

You can plot figures from matrices (directly or indirectly):

Special Plots

Multiple plots

You can plot multiple equations/matrices on the same graph using the 'Multiple values' item

Hints

Zooming is done with the zoom tool. If you roll your mouse wheel it zooms both axes together. If you hold 'control' at the same time it just zooms the vertical axis, and if you use 'shift' and the mouse wheel it zooms the horizontal axis.