solve 2 equations with 2 variables

#1 Posted: 8/23/2017 4:25:38 AM

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what is the best way to solve 2 equations with 2 variables?

example:

(Fa*2)+(Fb*10)+20=0
(Fa*3)+(Fb*9)+15=0

What is the easiest way to solve the 2 equations with 2 variables ?
What function can I use best to find the values of Fa & Fb?

Regards,

Sjoerd

#2 Posted: 8/23/2017 7:15:13 AM

Jean Giraud

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Group: User

There are more ways exemplified in the attached Smath.
Setup the system in traditional format, the solving
algebra follows ... Universal. Same approach will
optimize a data set for polynomial best fit.

Cheers, Jean

Solve [x,y,z] Compactum.sm (91 KiB) downloaded 74 time(s).

1 users liked this post

Davide Carpi 8/23/2017 7:19:00 AM

#3 Posted: 8/23/2017 7:31:09 AM

Martin Kraska

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Group: Moderator

The Solve function from the Maxima Plugin finds symbolic solutions, equations can be non-linear and involve units.

2017-08-23 12_22_08-SMath Studio 0.98.6398 - [Update17.sm_].png

The attached file is taken from the interactive handbook (available in the extension manager).
_Solve.sm (35 KiB) downloaded 218 time(s).

Martin Kraska Pre-configured portable distribution of SMath Studio: https://en.smath.info/wiki/SMath%20with%20Plugins.ashx

#4 Posted: 8/23/2017 11:07:04 AM

Jean Giraud

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Group: User

Wrote
What function can I use best solve

Implict solver works in the stable Smath 6179.

#5 Posted: 8/23/2017 6:32:45 PM

Sjoerd

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Many Thanks for the help sofar. I downloaded v14 + maxima en try to use the solve function, but I got the message as displayed in the enclosed file:

Translation of Dutch message: The reference of the object is not adjusted to an item of the object

What can be the problem ?

Another question: the solve option under the Calculation tab is grayed out. It seems I can not use this solve option. What can be the point ??

regards,

Sjoerd

#6 Posted: 8/23/2017 7:34:02 PM

Martin Kraska

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Group: Moderator

Wrote
Many Thanks for the help sofar. I downloaded v14 + maxima en try to use the solve function, but I got the message as displayed in the enclosed file:

Translation of Dutch message: The reference of the object is not adjusted to an item of the object

What can be the problem ?

What is v14? I recommend to use the latest nightly build of SMath and Maxima, see http://en.smath.info/forum/yaf_postsm11095_Maxima-Plugin.aspx#post11095.

Martin Kraska Pre-configured portable distribution of SMath Studio: https://en.smath.info/wiki/SMath%20with%20Plugins.ashx

#7 Posted: 8/24/2017 4:53:03 PM

Sjoerd

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I use version 14 as is visible in :

I use windows 10 . Can that be the problem.
Do I have to do some installation settings to get maxima running ?

I tested the solve.sm file, when I recalculate the page. Maxima starts up but keeps on calculating for a very very long time, without a solution!
Maxima reagiert nicht!

what can be the problem??

regards,

Sjoerd

#8 Posted: 8/24/2017 5:58:24 PM

Martin Kraska

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Group: Moderator

I can only handle problems with SMath 0.98.6398 and newer (nightly builds), at least if related to the Maxima plugin.
With this new version the configuration of the Maxima plugin is easy (I streamlined the settings dialog and fixed several bugs).

Just follow the instructions on http://en.smath.info/forum/yaf_postst2078_Maxima-Plugin.aspx. There have been reports of successful installation under Win10, however, I rund Win7 and thus rely on third party reports. Let me know if there are problems and also if everything goes well.

Martin Kraska Pre-configured portable distribution of SMath Studio: https://en.smath.info/wiki/SMath%20with%20Plugins.ashx

#9 Posted: 8/25/2017 8:37:48 AM

Jean Giraud

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Group: User

Wrote
what can be the problem??

None of the solving approach is correct.
0.5 sec visit 6179 to solve the patients.
Too big to make an image.

Jean

Solve System High accuracy.sm (115 KiB) downloaded 52 time(s).

#10 Posted: 8/25/2017 8:55:59 AM

Jean Giraud

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Group: User

... if it looks innocent to solve by hand, not so !

#11 Posted: 8/25/2017 12:23:23 PM

Jean Giraud

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Group: User

... rather, download this one. Last module fails after saving.
Very annoying that it works during construction but not after.

Solve System High accuracy.sm (116 KiB) downloaded 50 time(s).

#12 Posted: 8/25/2017 4:07:45 PM

Sjoerd

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In two versions I downloaded and try to run , the following message appears:

The versions I downloaded are:

The strange thing is that my Windows Defender software is already disabled !!?
In this way I am not able to start Smath at all !

#13 Posted: 8/25/2017 5:05:10 PM

Martin Kraska

1222 likes in 2150 posts.

Group: Moderator

The only change I did to the executable was to set the 32 bit flag which is required for the Mathcad user library interface to work (Steamtables and Special math functions libs, userefi plugin). If you don't need this, then replace the executable in the portable distribution by the one in the LINUX version (yes, even if you are under win).

If that doesn't work you can still try the installation procedure described in http://en.smath.info/forum/yaf_postst2078_Maxima-Plugin.aspx. This exclusively uses original installers.

Martin Kraska Pre-configured portable distribution of SMath Studio: https://en.smath.info/wiki/SMath%20with%20Plugins.ashx

#14 Posted: 8/25/2017 5:08:19 PM

Jean Giraud

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Group: User

Do you mean: you couldn't download none of the
work sheet I attached ? Strange Smath does not
start. Try to call from the icon in the Smath
main directory.

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