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Mathematics Visual Arts Mathematica Calculus Graphics and Visualization

ContourPlot gives a strange graphics for usial polynome (2 variables)

Alexey Podchufarov

Alexey Podchufarov, own

Posted 7 years ago

Hello, Community! A problem - simple command: ContourPlot[ 216 + 1728 b1 + 5184 b1^2 + 6912 b1^3 + 3456 b1^4 - 108 b2 - 648 b1 b2 - 1296 b1^2 b2 - 864 b1^3 b2 - 32 b2^2 - 128 b1 b2^2 - 128 b1^2 b2^2 + 12 b2^3 + 24 b1 b2^3 + 3 b2^4 == 0, {b2, -0.001, 0.001}, {b1, -0.5001, -0.4999}] draws smthng strange (impossible for any polynom!) There is a problem with limits of a picture - when i take another limits, picture is as i wait to see - So, the question - it's a problem of: program / (noname) comp / ContourPlot? UPD: When i use Manipulate - picture becomes more interesting: Manipulate[ ContourPlot[ 216 + 1728 b1 + 5184 b1^2 + 6912 b1^3 + 3456 b1^4 - 108 b2 - 648 b1 b2 - 1296 b1^2 b2 - 864 b1^3 b2 - 32 b2^2 - 128 b1 b2^2 - 128 b1^2 b2^2 + 12 b2^3 + 24 b1 b2^3 + 3 b2^4 == 0, {b2, -0.001, 0.001}, {b1, -0.5 - k, -0.5 + k}], {k, 0.00001, 0.01}] With big k - we see a straight line segment, with smaller - nothing, and with smallest - fantastic pics with no relation to given equation.

Hello, Community!

A problem - simple command:

ContourPlot[ 216 + 1728 b1 + 5184 b1^2 + 6912 b1^3 + 3456 b1^4 - 108 b2 - 648 b1 b2 - 1296 b1^2 b2 - 864 b1^3 b2 - 32 b2^2 - 128 b1 b2^2 - 
   128 b1^2 b2^2 + 12 b2^3 + 24 b1 b2^3 + 3 b2^4 == 0, {b2, -0.001,  0.001}, {b1, -0.5001, -0.4999}]

draws smthng strange (impossible for any polynom!)

There is a problem with limits of a picture - when i take another limits, picture is as i wait to see -

So, the question - it's a problem of: program / (noname) comp / ContourPlot?

UPD: When i use Manipulate - picture becomes more interesting:

Manipulate[ ContourPlot[ 216 + 1728 b1 + 5184 b1^2 + 6912 b1^3 + 3456 b1^4 - 108 b2 - 648 b1 b2 - 1296 b1^2 b2 - 864 b1^3 b2 - 32 b2^2 - 128 b1 b2^2 - 128 b1^2 b2^2 + 12 b2^3 + 24 b1 b2^3 + 3 b2^4 == 0, {b2, -0.001, 0.001}, {b1, -0.5 - k, -0.5 + k}], {k, 0.00001, 0.01}]

With big k - we see a straight line segment, with smaller - nothing, and with smallest - fantastic pics with no relation to given equation.

POSTED BY: Alexey Podchufarov

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Moderation Team

Moderation Team, WOLFRAM

Posted 7 years ago

Please make sure you know the rules: https://wolfr.am/READ-1ST The rules explain how to format your code properly. If you do not format code, it may become corrupted and useless to other members. Please EDIT your posts and make sure code blocks start on a new paragraph and look framed and colored like this. int = Integrate[1/(x^3 - 1), x]; Map[Framed, int, Infinity]