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Symbol math error?

ValeryOchkov
24-Ruby IV

Symbol math error?

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

 

ACCEPTED SOLUTION

Accepted Solutions

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.

View solution in original post

14 REPLIES 14
LucMeekes
23-Emerald III
(To:ValeryOchkov)

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

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!

 

Maple without Explicit plot

Nautilus-Maple-2.png

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

nau1.png

Viktor

nautilus.jpg

Viktor

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. 

Nautilus.gif

Viktor, thanks for the picture.

See please the animation-solution:

Nautilus.gif

One more solution - a systen of equations!

What curves are false?

Nautilus-System.png


@ValeryOchkov wrote:

 

What curves are false?

 

 


In what sense? Mathematical? Physical?

Viktor

Все кроме двух замкнутых!

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

Nautilus-System.png

Same error in Mathematica too Robot Sad

Mathematica.png

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.

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