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Offline Mido0  
#1 Posted : 05 April 2022 21:45:27(UTC)
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hi,
I used the Solve function a lot before but for some reason it does not work for this simple example.
I need to get the RayLeigh Damping factors alpha and beta using two frequencies, so two simple simultaneous equations should do it. tried using Solve but no luck.
Does anyone know why it is not solving?

Thanks in advance

Solve.jpg test.sm (6kb) downloaded 7 time(s).
Offline PompelmoTell  
#2 Posted : 05 April 2022 22:39:40(UTC)
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test_sergio.sm (9kb) downloaded 19 time(s).
sergio

Edited by user 05 April 2022 22:45:15(UTC)  | Reason: Not specified

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Offline overlord  
#3 Posted : 06 April 2022 00:24:50(UTC)
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You can use roots() for your function. And a vectorize() can simplify it.
However, to use Assign() you will need this function to merge vars and solutions.

Regards

Assign_without_Maxima Solve().sm (8kb) downloaded 12 time(s).

2022-04-06_00-21.png
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Offline Mido0  
#4 Posted : 06 April 2022 04:22:48(UTC)
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Thanks Overlord, PompelmoTell, greatly appreciated!!
Offline Kenny Lemens  
#5 Posted : 06 April 2022 16:28:07(UTC)
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Greetings,

Another approach would be to use some elbow grease, you can substitute terms by hand and solve for 𝛼 and 𝛽:

Keypress (You can copy/paste the following into your worksheet):
Code:
α:{2*D*ω.1*ω.2}/{ω.1+ω.2}
β:α/{ω.1*ω.2}

*NOTE: ω.1 and ω.2 shown above are variables with subscript, they are not vectors ω[1 and ω[2; You should be able to substitute ω.1 for ω[1 if that serves your purposes.

- - - [SMath] Simultaneous Equations.jpg


- Kenny Lemens, P.E.
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Offline Ber7  
#6 Posted : 06 April 2022 17:40:36(UTC)
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If the damping coefficients are denoted by α1 and α2, you can use the function al_nlegsoive
test.sm (7kb) downloaded 9 time(s).
test.png
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Offline Jean Giraud  
#7 Posted : 07 April 2022 17:08:53(UTC)
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...

FindRoot.PNG
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Offline Jean Giraud  
#8 Posted : 07 April 2022 19:43:03(UTC)
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... more in there from native Smath code.

Solve FindRoot FORUM.sm (11kb) downloaded 8 time(s).
Offline overlord  
#9 Posted : 07 April 2022 23:27:55(UTC)
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solving with uni's latest addition mathcad blocks;
you wouldn't need Eq: actually, but it can be shown.

mathblock.sm (6kb) downloaded 8 time(s).

2022-04-07_23-26.png

Edited by user 07 April 2022 23:29:29(UTC)  | Reason: Not specified

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Offline overlord  
#10 Posted : 08 April 2022 00:19:34(UTC)
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I think this is the most sophisticated method of my way.
It can get unknowns from equation, solve them.
In the end assigns numerical values to unknowns.
You don't need to define alpha or beta or any variable.
All process is automatic.

Regards

mathblock_v2.sm (6kb) downloaded 11 time(s).

2022-04-08_01-54.png

There is also this way for guess define.

2022-04-08_01-57.png

Edited by user 08 April 2022 01:58:41(UTC)  | Reason: Not specified

Offline Ber7  
#11 Posted : 08 April 2022 08:19:42(UTC)
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Originally Posted by: overlord Go to Quoted Post
I think this is the most sophisticated method of my way.
It can get unknowns from equation, solve them.
In the end assigns numerical values to unknowns.
You don't need to define alpha or beta or any variable.
All process is automatic.

Regards
There is also this way for guess define.


2022-04-08_01-57.png

This is good, but for a system of linear equations(our case), the guess can be arbitrary.

Edited by user 08 April 2022 08:30:49(UTC)  | Reason: Not specified

Offline mkraska  
#12 Posted : 09 April 2022 02:04:07(UTC)
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And finally a version with Solve() and list injection region:

mathblock_Solve.png
mathblock_Solve.sm (5kb) downloaded 11 time(s).
Martin Kraska

Pre-configured portable distribution of SMath Studio: https://en.smath.info/wi...th%20with%20Plugins.ashx
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Offline Kenny Lemens  
#13 Posted : 11 April 2022 15:57:44(UTC)
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Greetings,

If plugins are considered, you can also consider the use of Maple:
- - - [SMath] Maple - Simulatneous Equ..jpg

In the image I posted, the 'equal sign' shown on those two equations are actually symbolic equals; keypress: [ctrl] + [.] instead of keypress [=].

Kenny Lemens, P.E.
Offline Razonar  
#14 Posted : 11 April 2022 22:44:08(UTC)
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Hi. The isol solution, using only the Mathcad block plugin.

img1.png

isol_example.sm (69kb) downloaded 20 time(s).
isol_example.pdf (35kb) downloaded 9 time(s).

Best regards.
Alvaro.
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Offline Mido0  
#15 Posted : 14 April 2022 18:10:17(UTC)
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Thank you all for the feedback, is there a literature or manual to explain the Mathcad block plugin?
Thanks
Offline Jean Giraud  
#16 Posted : 14 April 2022 20:54:00(UTC)
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Originally Posted by: Mido0 Go to Quoted Post
Thank you all for the feedback, is there a literature or manual to explain the Mathcad block plugin ?

For that particular example, maple is an algebraic export.
Mathcad block has not yet been exemplified in Smath Community
of what it can do vs what native Smath can't.
Cheers ... Jean.

Codes Solve.sm (13kb) downloaded 5 time(s).
Offline Jean Giraud  
#17 Posted : 15 April 2022 01:43:45(UTC)
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Exercise the Mathcad bloc

MathBloc Test.PNG
Offline overlord  
#18 Posted : 15 April 2022 02:19:07(UTC)
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Originally Posted by: Mido0 Go to Quoted Post
Thank you all for the feedback, is there a literature or manual to explain the Mathcad block plugin?
Thanks

We have what Viacheslav provided us.
There are some samples or functions too which individual users uploaded.
You can look the extension page for some examples.
And there are some samples in forum topic that users posted.
It may be a small bunch, but we try to understand its capabilities.
This feature/plugin is also new to us.

Regards

https://en.smath.com/forum/yaf_postst726_Mathcad-Toolbox.aspx
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