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From: NELSON%VWSCYG@vmsd.oac.uci.edu (Matthew A. Nelson)
Newsgroups: comp.sys.handhelds
Subject: plotting relations
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Date: 11 Dec 90 16:23:00 GMT
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>From: akcs.mitchell@hpcvbbs.UUCP (Mitchell Dickerman)

>
>Long ago, I had a wonderful program that plotted relations, i.e.
>if you gave it X^2+Y^2-1, it drew the unit circle. I would love to
>see a program like this for my 48, but I'm not much of a programmer.
>In order to plot f(x,y)=0, one would have to begin with the pixel
>in the upper left hand corner, and check the 3 adjacent pixels and
>compare the sign of f(x,y) evaluated at those points. If a sign change
>occured, it indicates a solution of f(x,y)=0, and that pixel should
>be turned on. Am I making sense? Can someone give me a hand implementing
>this?
>
>Mitch

Read the manual.  Store 'SQ(x)+SQ(y)=1' as EQ (via STEQ in PLOT menu), then
go into the PLOT PTYPE menu and hit CONIC.  Now, when you go into the PLOTR
and do an ERASE DRAW, you'll get your unit circle.  The 48 does a variety of
fancy plots; read the manual.

-matt