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24-Ruby III

## 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)

1 ACCEPTED SOLUTION

Accepted Solutions
24-Ruby III
(To: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.

14 REPLIES 14
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:

Luc

24-Ruby III
(To:LucMeekes)

Thanks, Luc!

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

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

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

24-Ruby III
(To:ValeryOchkov)

Maple without Explicit plot

13-Aquamarine
(To:ValeryOchkov)

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

Viktor
13-Aquamarine
(To:ViktorKorobov)

Viktor
24-Ruby III
(To:ViktorKorobov)

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.

24-Ruby III
(To:ViktorKorobov)

24-Ruby III
(To:ViktorKorobov)

Viktor, thanks for the picture.

24-Ruby III
(To:ValeryOchkov)

One more solution - a systen of equations!

What curves are false?

13-Aquamarine
(To:ValeryOchkov)

@ValeryOchkov wrote:

What curves are false?

In what sense? Mathematical? Physical?

Viktor
24-Ruby III
(To:ViktorKorobov)

Все кроме двух замкнутых!

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

24-Ruby III
(To:ValeryOchkov)

Same error in Mathematica too

24-Ruby III
(To: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.

24-Ruby III
(To:ValeryOchkov)
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