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How to draw curves (cardioid, lemniscate, devil's curve)?

  1. Aug 9, 2015 #1
    Hi everyone,

    Thanks for visiting my post. I was wondering if you guys know what kind of software I must use to draw complicated curves. I already have the equations. For example, for lemniscate I would use following:

    I appreciate the help.
  2. jcsd
  3. Aug 9, 2015 #2


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    There are many programs that can plot those curves.
    Your specific example are two straight lines.
  4. Aug 9, 2015 #3

    The example that I posted is Lemniscate's equation in Cartesian coordinates. Please refer to https://en.wikipedia.org/wiki/Lemniscate_of_Bernoulli
    Anyway, I have the equations and I would like to draw the curves.

    And as you said, I know that there are many software programs available. Can you provide me with a name.

  5. Aug 9, 2015 #4


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    Your formula is missing a square on the left side.

    This list has many programs.
    Gnuplot, Maple, Mathematica and Matlab are some of the more prominent plotting programs in this list.
    Then why did you ask which program you "must" use if there are so many options?

    Edit: We don't delete threads, but I can close this one.
    Last edited: Aug 9, 2015
  6. Aug 9, 2015 #5


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    Follow the link in post #2 and you will have one name. :smile:
  7. Aug 9, 2015 #6
    The equation is 2(x^2+y^2)^2=25(x^2-y^2). I wrote my post in a hurry and didn't see the error until now.

    Also as for the usage of the word "must", it could have easily been replaced with words like "could, should, may", etc. It's just a technicality. I apologize if you misunderstood.

    Thanks for the list. It will come in handy.
  8. Aug 9, 2015 #7
    Well, one name, two names, three names.

    Happy to be given a list eventually. I will def check out Gnuplot and Maple.
  9. Aug 9, 2015 #8
    Check geogebra. It's free and it can handle these kind of implicit equations perfectly.
  10. Aug 9, 2015 #9

    It's great. Thank you. I am trying it out now. I am trying to use CAS but it doesn't seem to plot. Any ideas?
  11. Aug 9, 2015 #10
    What's CAS? Is that part of geogebra, or does it mean you're using another Computer Algebra System?
    If you're using geogebra, you just need to go all the way below to "input" and type your equation 2(x^2+y^2)^2=25(x^2-y^2). That should plot it immediately.
  12. Aug 9, 2015 #11
    CAS is part of geogebra. I just downloaded it and I am looking at it now. O.K. I will do that.
  13. Aug 9, 2015 #12
    Oh ok, I see it now. You don't need this CAS at all. It's better just to close that window.
  14. Aug 9, 2015 #13
    Alright. Do you think it'd be ok if I pm you some time later? (currently I am working on something). You are kind. I really appreciate your help.
  15. Aug 9, 2015 #14
    Sure, I don't mind.
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