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 >>> to be answered. >>> >>> 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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