Re: A New Scientist article verified with Mathematica

• To: mathgroup at smc.vnet.net
• Subject: [mg107337] Re: A New Scientist article verified with Mathematica
• From: sigismond kmiecik <sigismond.kmiecik at wanadoo.fr>
• Date: Tue, 9 Feb 2010 07:59:10 -0500 (EST)
• References: <hkr3s0\$acs\$1@smc.vnet.net>

```John Fultz a =E9crit :
> On Sun, 7 Feb 2010 06:14:31 -0500 (EST), sigismond kmiecik wrote:
>> sigismond kmiecik a E9crit :
>>> Hello to everybody
>>>
>>> In  the last Xmas issue of the New Scientist magazine there is on page
>>> 40 a small article about the continuity principle applied to
>>> intersecting circles.
>>> I used Mathematica to confirm its conclusions but some questions remain
>>>
>>> These circles are represented by
>>>
>>> Show[{Graphics[{Red, Circle[{0, 0}, 2]}], Graphics[Circle[{2, 0}, 2]],
>>> Graphics[{Red, Dashed, Circle[{5, 0}, 2]}]}, AxesOrigin -> {0, 0},
>>> PlotRange -> {{-3, 8}, {-3, 3}}, Axes -> True ]
>>>
>>> The intersection coordinates of the red (non-dashed) and black circle is
>>> found by:
>>>
>>> Solve [{ x^2 + y^2 - 4 == 0, (x - 2)^2 + y^2  - 4  == 0 }, {x, y}
>>> ]
>>>
>>> And there is indeed an imaginary intersection of the red and red-dashed
>>> circle even if they are not touching -  as found by:
>>>
>>> Solve [{ x^2 + y^2 - 4 == 0, (x - 5)^2 + y^2  - 4  == 0 }, {x, y}
>>> ]
>>>
>>> My questions are:
>>> - Is there a way to draw  with Mathematica these three circles using
>>> their cartesian equations and not the Circle graphics primitive
>> 92 ?
>>> - How can I transform the list of rules solutions to the last equation
>>> above  in order to represent them on the complex plane  (I thought about
>>> a ListPlot [{Re[],Im[]}=85  but I know not  enough of Mathematica to
>>> obtain that)
>>> - And last is there a Mathematica notebook on the web dealing with the
>>> intersection of  planes with cones?
>>>
>>> Thanks
>>>
>>> Sigismond Kmiecik
>>>
>> Hi
>> THe two Solve expressions that I copied/pasted from a Mathematica
>> notebook to Thunderbird
>> became corrupted after being  added to the forum. What precautions must
>> I take in order to
>> avoid that ?
>> Thanks
>> Sigismond Kmiecik
>
> The corruption I saw was an = sign at the end of some of the lines.  That's what
> you saw too, right?  This doesn't have anything to do with Mathematica, as you
> may have suspected.
>
> I'm not for certain, but I strongly suspect that this generally is caused by
> sending some sort of combined HTML/plain-text email to the list, and the process
> that Steve uses when moderating/forwarding to the list to strip it down to plain
> text (which is the only format he'll ever post onto the forum...a decision I
> happen to support, incidentally).  The extra markings look like MIME markup of
> the type that gets included when you have combined messages like that.
>
> I think that if you set Thunderbird to send email as plain text only, you
> wouldn't see this problem.
>
> [Many posts that have either html or non-ascii characters in them may
> get corrupted during processing.  It is best to make sure posts have
> no html in them or as attachments and no non-ascii contents - moderator]
>
>
> Sincerely,
>
> John Fultz
> jfultz at wolfram.com
> User Interface Group
> Wolfram Research, Inc.
>
You are correct John, the corruption came from the added = at the end
some Mathematica code lines.
For a next entry in the forum I will as suggested copy as plain text
from Mathermatica and send as text  only (which is an option with
Thunderbird).
Regards
Sigismond K.

```

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