Make graphs smooth vertically as well as vertically (if you don't see what I mean, compare y = 2x with y = 0.5x) and generally improve the smoothing (with this, I suppose). In fact, I've played around with my own (rather ineffective) method: try changing the smoothing tolerance and replotting...
Add a zoom function (this may involve having to implement a system recording which graphs have been plotted so they can be redrawn with a new scale factor) or a scaling coefficient when to be used when plotting a graph initially (easier). In fact, currently graphs of the form y = xn are plotted as y = (x/100)n...
Add support for polynomials
Add a scale
Incorporate my awesome (well, rubbish) VB6 linear simultaneous equation solver
AWESOME: If you can, try to run this in Opera or Safari with a grid size of about 200. It's significantly more awesome that way.
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