1

Using 

tmp = ContourPlot[{y^4 + 6 x^3*y + x^8 == 0, y - x^3 == 0}, {x, -5, 
   5}, {y, -5, 5}]

How can I get the pair values used to plot these two curves?

For example: x^2 + y^2 - 1 = 0 , (2,Sqrt(-3)) is a point of the curve.

Thank you.

kglr
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Luiz Meier
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  • For example, (2,√−3) is a point of the curve defined by x^2 + y^2 − 1 = 0 and the usual unit circle is the real part of this curve. The term "unit circle" may refer to all the complex points as well to only the real points, the exact meaning being usually clear from the context. The equation x^2 + y^2 + 1 = 0 defines an algebraic curve, whose real part is empty. – Luiz Meier Aug 16 '14 at 00:16
  • @MichaelE2 : I wish to see the entire set or a part of the pairs (x1,y1) , (xn,yn) of a ContourPlot and not to save it to a file. Thanks. – Luiz Meier Aug 16 '14 at 00:19
  • Let me try to explain again: How can I get the values used to plot the two algebraic curves in the original plot? The 'duplicate question' don't have the answer I am asking for. – Luiz Meier Aug 16 '14 at 00:25
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    The Cases command in the answer to the duplicate yields the points (pairs) you seek. The answer says nothing about saving to a file -- the Export command is irrelevant. – Michael E2 Aug 16 '14 at 00:38
  • @MichaelE2 You mean "the question", for sure – Dr. belisarius Aug 16 '14 at 00:41
  • Perhaps you're looking for Reduce[{y^4 + 6 x^3*y + x^8 == 0, y - x^3 == 0}, {x, y}, Cubics -> True] – Dr. belisarius Aug 16 '14 at 00:45
  • @MichaelE2 I'd noticed that you answered a question about interceptation of two curves. It is exactly what I want to do also. I'm reading a book where it asks to show how many times the curves intercept at the origin. I was able to find it using Sage but I'm new to Mathematica, so, I don't know how to use the Cases (yes, I read the help) neither how to use a kind of Solve or to test how many times curve1 == curve2 at (0,0). – Luiz Meier Aug 16 '14 at 00:45
  • @belisarius : almost that! – Luiz Meier Aug 16 '14 at 00:47
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    @LuizRobertoMeier I see, I think: You want the points of intersection? That's not what the question asks as currently stated. – Michael E2 Aug 16 '14 at 00:50
  • @MichaelE2 Can I rename the question or should I create another one? – Luiz Meier Aug 16 '14 at 00:54
  • @LuizRobertoMeier I suppose either way would be fine -- no one has answered this one so far. – Michael E2 Aug 16 '14 at 01:19
  • I recommend renaming; there is no benefit to creating a new Question when there are not existing answers that would be invalidated by an edit. – Mr.Wizard Aug 16 '14 at 03:53

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