Re: ImplicitPlot errors

• To: mathgroup at smc.vnet.net
• Subject: [mg75146] Re: ImplicitPlot errors
• From: "David Rees" <w3bdevilREMOVE at THISw3bdevil.com>
• Date: Wed, 18 Apr 2007 05:07:30 -0400 (EDT)
• References: <evvbfs\$9q5\$1@smc.vnet.net>

```To all of those who replied, thanks, but I found the problem.

I entered the equation as "2xy" rather than "2x*y", when I do that
Mathematica has no complaint.

I also had a problem with an equation involving Euler's constant, I thought
the "e" character (or the stylised "e" symbol in the toolbox) automatically
represented Euler's constant in this context. My bad, I didn't realise it
was uppercase "E" (my calculator, a Ti-83 uses uppercase E to define Power
10 exponents and lowercase e for Euler's).

Once again, thanks.

"David Rees" <w3bdevilREMOVE at THISw3bdevil.com> wrote in message
news:evvbfs\$9q5\$1 at smc.vnet.net...
> Hi,
>
> I've been trying to get ImplicitPlot to plot an implicit function
> (naturally
> ;) ), but it throws errors to cryptic for me, even when copying and
> pasting
> from the Mathematica function reference.
>
> In[40]:= ImplicitPlot[{x^2 + x*y + y^2 == 7, y == 2*Sqrt[7/3]}, {x, -5,
> 5}]
>
> ImplicitPlot::var :
>
> Equation x^2+x
> Function[x,x^2+2xy-3y^2-16]+Function[x,x^2+2xy-3<<1>>-16]^2==7 does not
> have
> a single variable other than x
>
> ImplicitPlot::var :
>
> Equation Function[x,x^2+2xy-3y^2-16]==2Sqrt(7/3) does not have a single
> variable other than x
>
> Out[40]:=\!\(ImplicitPlot[{x\^2 + x\ Function[x, x\^2 + 2\
>          xy - 3\ y\^2 - 16] + Function[
>              x, x\^2 + 2\ xy - 3\ y\^2 - 16]\^2 == 7, Function[x, x\^2 +
> 2\
>              xy - 3\ y\^2 - 16] == 2\ \@\(7\/3\), x == 2\ \@\(7\/3\)}, {x,
> \
> \(-5\), 5}, {Function[x, x\^2 + 2\ xy - 3\ y\^2 - 16], \(-5\), 5}]\)
>
>
>
> What am I doing wrong? Even ImplicitPlot[x+y==2,{x,-4,4}] fails.
>
> Thanks
>
>
>

```

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