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Offline elis02  
#1 Posted : 02 November 2023 03:42:25(UTC)
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test_s_math.sm (10kb) downloaded 7 time(s).

Hi I'm trying to solve an equation (see in the attached file) where the solution , the number should be small but for some reason which i can't understand , the app doesn't provide me a solution.
Why is that?

P.S
I'm new to Smath but it seems like it can help a lot with calculations.

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Offline oscampo  
#2 Posted : 02 November 2023 05:59:25(UTC)
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Hi Elis02,
Native solve() is nota robust solver, so it's convenient use functions as Solve() from Maxima plugin or FindRoot() from Non Linear Solvers plugin.

You need provide a value to x(t) for asking for a value of t that satisfies the equation, in the form "x(t)=k, t" where k is the value you expect obtain when replace for t:



Best,
Oscar
Offline overlord  
#3 Posted : 02 November 2023 06:09:46(UTC)
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Numeric solvers don't like units.
Either don't use them or add units to solvers.
Entering a range/interval will help for solve().
Findroot() won't need unit addition btw.

Regards

test_s_math_solved.sm (13kb) downloaded 7 time(s).

2023-11-01_20-07.png
thanks 2 users thanked overlord for this useful post.
on 02/11/2023(UTC),  on 03/11/2023(UTC)
Offline overlord  
#4 Posted : 03 November 2023 08:32:22(UTC)
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Jean has ignored units, manually input E1.
As usual, these made him totally wrong.
He doesn't have correct answer.

This is Jean's plot;
2023-11-02_22-27.png

This what it should be;
2023-11-02_22-26.png

If you don't know, then don't say.
Your mistakes are harming this community.
thanks 3 users thanked overlord for this useful post.
on 03/11/2023(UTC),  on 03/11/2023(UTC),  on 03/11/2023(UTC)
Offline Jean Giraud  
#5 Posted : 03 November 2023 23:09:30(UTC)
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Windows handles arithmetic [+,-,*,/] in the range 10^ ± 307.
Your ^-19 is so small that the quadratic term vanishes.
What's left is the linear term and the shift system.
On the other hand, some function may be granular.
Granular in the sense that they many not compute exactly.
The one best known from Mathematica.
Jean
Offline overlord  
#6 Posted : 04 November 2023 00:17:56(UTC)
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Originally Posted by: Jean Giraud Go to Quoted Post
Windows handles arithmetic [+,-,*,/] in the range 10^ ± 307.
Your ^-19 is so small that the quadratic term vanishes.

No it doesn't vanishes.
You are simply not capable to work with units.
Anything involves physical quantities, you are wrong there.
This is not the first you act like a buffoon.
You couldn't write a simple formula, admit it.
In fact, you are a horribly wretched engineer.

Jean, look and learn. This is how you eliminate units.
Btw, why did you delete all your meaningless replies?

2023-11-03_14-16.png

Can you see the problem Jean?
You forgot your unit conversions.
m_Ar and E1 needs magick numbers in your approach.
If you would capable to work with units, no coefficients needed.
Everything is simple, clean, easier to apprehend, much easier to manipulate with units.

Edited by user 04 November 2023 00:45:39(UTC)  | Reason: Not specified

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on 04/11/2023(UTC),  on 04/11/2023(UTC)
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