solve small numbers

solve small numbers - trying to solve an equation with small number solution - Messages

#1 Posted: 11/1/2023 9:42:25 PM
elis02

elis02

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test_s_math.sm (9 KiB) downloaded 30 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.
#2 Posted: 11/1/2023 11:59:25 PM
Oscar Campo

Oscar Campo

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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:

[albumimg]1697[/albumimg]

Best,
Oscar
#3 Posted: 11/2/2023 12:09:46 AM
overlord

overlord

552 likes in 1332 posts.

Group: Moderator

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 (12 KiB) downloaded 33 time(s).

2023-11-01_20-07.png
2 users liked this post
Oscar Campo 11/2/2023 12:13:00 AM, NDTM Amarasekera 11/2/2023 7:07:00 PM
#4 Posted: 11/3/2023 2:32:22 AM
overlord

overlord

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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.
3 users liked this post
Alvaro Diaz Falconi 11/3/2023 2:50:00 AM, Oscar Campo 11/3/2023 5:24:00 AM, NDTM Amarasekera 11/3/2023 9:00:00 AM
#5 Posted: 11/3/2023 5:09:30 PM
Jean Giraud

Jean Giraud

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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
#6 Posted: 11/3/2023 6:17:56 PM
overlord

overlord

552 likes in 1332 posts.

Group: Moderator

Wrote

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.
2 users liked this post
Oscar Campo 11/3/2023 11:30:00 PM, Alvaro Diaz Falconi 11/4/2023 12:16:00 AM
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