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24-Ruby IV
ValeryOchkov24-Ruby IV
24-Ruby IV
October 13, 2017
Solved

Symbol math error?

  • October 13, 2017
  • 6 replies
  • 6916 views

Is it an error in Mathcad (and Maple) symbolic math or I do not understand something? (See please the attached Mathcad 15 file)

Nautilus-eng.png

 

Best answer by ValeryOchkov

It seems to me that I know the reason for this error.
The engine of symbolic mathematics reduces the solution of a complex equation to the solution of a quadratic equation. Here we have two roots, one of which is correct, and the other is false.

6 replies

L
LucMeekes23-Emerald IV
23-Emerald IV
October 13, 2017

That does not seem like Maple output (the roots are written with the square root symbol, rather than using a power of 1/2), I guess you're using Mathcad 15, not 13 or before.

Anyway, the same problems occur in Mathcad 11, with Maple, as soon as r is set enough below 3:

LM_20171013_Submarine.png

Luc

    V
    24-Ruby IV
    ValeryOchkov24-Ruby IVAuthor
    24-Ruby IV
    October 13, 2017

    Thanks, Luc!

    No error by using the implicit plot in Maple - we have no false branch of the curve

    Nautilus-Maple-1.png

    We can not plot the implicit function in Mathcad. But if you can not, but really want, then you can

    Nautilus-Mathcad-1.png

    We have no false branch of the curve in Mathcad too!

     

    V
    24-Ruby IV
    ValeryOchkov24-Ruby IVAuthor
    24-Ruby IV
    October 13, 2017

    Maple without Explicit plot

    Nautilus-Maple-2.png

    V
    ViktorKorobov1-Visitor
    1-Visitor
    October 13, 2017

    ВФ! Я "отсек" физически бессмысленные решения. Вот что получилось.

    nau1.png

    V
    ViktorKorobov1-Visitor
    1-Visitor
    October 13, 2017

    nautilus.jpg

    V
    24-Ruby IV
    ValeryOchkov24-Ruby IVAuthor
    24-Ruby IV
    October 14, 2017

    Thanks, Viktor!

    But we are talking (толкуем) not about sizes one body - real or fiction, but about the symbolic math of Mathcad and Maple. What is it - a bug or our not understanding this powerful tool. 

    V
    24-Ruby IV
    ValeryOchkov24-Ruby IVAuthor
    24-Ruby IV
    October 14, 2017

    One more solution - a systen of equations!

    What curves are false?

    Nautilus-System.png

    V
    ViktorKorobov1-Visitor
    1-Visitor
    October 14, 2017
    @ValeryOchkov wrote:

     

    What curves are false?

     

     

    In what sense? Mathematical? Physical?

    V
    24-Ruby IV
    ValeryOchkov24-Ruby IVAuthor
    24-Ruby IV
    October 14, 2017

    Все кроме двух замкнутых!

    All curves are false except two closed! The red for L and blue for H!

    Nautilus-System.png

    V
    24-Ruby IV
    ValeryOchkov24-Ruby IVAuthor
    24-Ruby IV
    October 19, 2017

    Same error in Mathematica too Robot Sad

    Mathematica.png

    V
    24-Ruby IV
    ValeryOchkov24-Ruby IVAuthorAnswer
    24-Ruby IV
    October 19, 2017

    It seems to me that I know the reason for this error.
    The engine of symbolic mathematics reduces the solution of a complex equation to the solution of a quadratic equation. Here we have two roots, one of which is correct, and the other is false.

    V
    24-Ruby IV
    ValeryOchkov24-Ruby IVAuthor
    24-Ruby IV
    December 5, 2020

    See please about this bug

    The article "Symbolic Computation to Solving an Irrational Equation on Based Symmetric Polynomials Method" 

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