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Offline moaojanuel  
#1 Posted : 27 February 2018 13:10:25(UTC)
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Howdy,

I am relatively new to SMath (have used Mathcad in the past). I am trying to use SMath to run some engineering calculations. Particularly, I am interested in solving equations - I have used 'solve' function, but always get a "no real roots" message (see file attached).

Can someone help out?

Many thanks in advance!

J
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Offline Jean Giraud  
#2 Posted : 27 February 2018 16:44:46(UTC)
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Originally Posted by: moaojanuel Go to Quoted Post
I am relatively new to SMath (have used Mathcad in the past). I am trying to use SMath to run some engineering calculations. Particularly, I am interested in solving equations - I have used 'solve' function, but always get a "no real roots" message (see file attached).

Can someone help out?

Many thanks in advance!

Solving means a lot in Engineering works.
No real roots, indicates the solver is ill posed [generally]
Please, don't hesitate to post your problem, there is great expertise in Smath Community.

Maths bitcoin.sm (37kb) downloaded 76 time(s).
Solve General.sm (139kb) downloaded 116 time(s).
Solve TREASURY_0 [General].sm (120kb) downloaded 60 time(s).
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Offline Davide Carpi  
#3 Posted : 27 February 2018 19:47:20(UTC)
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Probably are you using the solve(2) function instead of the the solve(4) one (4 arguments, last 2 are the limits of the range where to search the roots)
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Offline moaojanuel  
#4 Posted : 27 February 2018 20:03:47(UTC)
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Many thanks ALL for your valuable responses. While I understand what you are saying/showing on your templates, I still haven't managed to figure out what is wrong with the way the solve function is being employed. I have changed the roots range (-100, +100), tried the solve with 4arguments, and still nothing. Is there any chance someone could have a look at the file I have attached originally?

Many thanks,
J
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Offline Davide Carpi  
#5 Posted : 27 February 2018 20:40:57(UTC)
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Originally Posted by: moaojanuel Go to Quoted Post
Is there any chance someone could have a look at the file I have attached originally?


There aren't attachments in your posts Good

Quote:
  1. 2018-02-24 19_32_16-Edit post.png

  2. 2018-02-24 19_32_34-Edit post.png

  3. 2018-02-24 19_32_44-Nessun file selezionato..png

  4. 2018-02-24 19_33_24-Edit post.png

Edited by user 27 February 2018 20:44:43(UTC)  | Reason: Not specified

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Offline Jean Giraud  
#6 Posted : 27 February 2018 21:37:49(UTC)
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Originally Posted by: moaojanuel Go to Quoted Post
Is there any chance someone could have a look at the file I have attached originally?

There is no *.sm document attached !
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Offline Jean Giraud  
#7 Posted : 27 February 2018 23:10:19(UTC)
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OVNIsolve.PNG
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Offline moaojanuel  
#8 Posted : 02 March 2018 15:46:16(UTC)
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(Please ignore my post below - I can see the files have been uploaded after all Cool

Iff someone could have a look at the .sm file I have attached, I would be very grateful.

Many thanks,
Joao

SMath_equation solver test.zip (2kb) downloaded 46 time(s).

SMath_equation solver test.sm (9kb) downloaded 58 time(s).

SMath_equation solver test.sm (9kb) downloaded 60 time(s).

Hi ALL,

Many thanks for you interest and responses. Apologies for not having responded but I have been away from the office. I am trying to attach an .sm file, but for some reason this is not working... Any thoughts?

Thanks,
Joao

Edited by user 02 March 2018 15:48:49(UTC)  | Reason: attachment was uploaded after all
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Offline Jean Giraud  
#9 Posted : 02 March 2018 16:31:55(UTC)
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Will be back later during the day
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Offline mkraska  
#10 Posted : 02 March 2018 20:16:58(UTC)
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solvers.png
solvers.sm (18kb) downloaded 64 time(s).
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thanks 6 users thanked mkraska for this useful post.
on 02/03/2018(UTC),  on 02/03/2018(UTC),  on 02/03/2018(UTC),  on 03/03/2018(UTC),  on 03/03/2018(UTC),  on 03/03/2018(UTC)
Offline Jean Giraud  
#11 Posted : 03 March 2018 16:59:27(UTC)
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Originally Posted by: moaojanuel Go to Quoted Post
Iff someone could have a look at the .sm file I have attached, I would be very grateful.


"NO real roots" from the solve bloc is an absolute pest [not to say stupid].

SolveWisely.PNG

SMath_equation solver test (1).sm (12kb) downloaded 81 time(s).
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Offline moaojanuel  
#12 Posted : 07 March 2018 13:18:35(UTC)
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Dear ALL,

Many thanks for your incredible support! I am in awe for the depth of knowledge herein displayed.

With regards to your responses, I appreciate the need to make an appropriate substitution to overcome the fact that solve can't handle units in the variable; However, I can´t seem to assign the unit to the variable, within the equation (apologies for being thick). I've tried typing x'm, tried using ctrl+w to assign meters unit to x, but still haven't managed to make it work. A bit frustrating... If anyone could be so kind to shed some light here, that would be greatly appreciated.

Many thanks,
J

Edited by moderator 29 March 2018 12:49:15(UTC)  | Reason: marked as SOLVED
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Offline mkraska  
#13 Posted : 07 March 2018 19:08:03(UTC)
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Originally Posted by: moaojanuel Go to Quoted Post
Dear ALL,

Many thanks for your incredible support! I am in awe for the depth of knowledge herein displayed.

With regards to your responses, I appreciate the need to make an appropriate substitution to overcome the fact that solve can't handle units in the variable; However, I can´t seem to assign the unit to the variable, within the equation (apologies for being thick). I've tried typing x'm, tried using ctrl+w to assign meters unit to x, but still haven't managed to make it work. A bit frustrating... If anyone could be so kind to shed some light here, that would be greatly appreciated.

Many thanks,
J




Type x*'m or x* and then insert the unit from the dialog into the empty placeholder in the right of the multiplication dot.

Multiplication operators in front of units aren't shown.
Martin Kraska

Pre-configured portable distribution of SMath Studio: https://smath.com/wiki/SMath_with_Plugins.ashx
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Offline Jean Giraud  
#14 Posted : 08 March 2018 07:50:22(UTC)
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Originally Posted by: moaojanuel Go to Quoted Post
Many thanks for your incredible support! I am in awe for the depth of knowledge herein displayed.

With regards to your responses, I appreciate the need to make an appropriate substitution to overcome the fact that solve can't handle units in the variable; However, I can´t seem to assign the unit to the variable, within the equation (apologies for being thick). I've tried typing x'm, tried using ctrl w to assign meters unit to x, but still haven't managed to make it work. A bit frustrating... If anyone could be so kind to shed some light here, that would be greatly appreciated.


You are debating with the Unit SI as implemented in Smath [Mathcad ...]
You may pacify your soul on several counts:
1. maths are unit less
2. ISO standards have their own units [most generally from SI derived units].
... therefore converting automatically bar in Pa ... etc.
3. Engineering formulas are constructed around the appropriate Units
... therefore no need to freak them more.
4. Consider this example: you have a formula, from which you can directly/indirectly
compute the arc length ... in what SI units Watson ???
... simple Sherlook ... in "UnitGraphic" that you can meter in year-light/micrometer ...
5. How did we do in the age of the slide rule, in the age of paper/pencil/log tables ?
6. Was Sputnik launched from SI unit software ?
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Offline jdoe1  
#15 Posted : 29 December 2019 04:19:53(UTC)
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I'm having a similar problem, it works on wolfram and symbolab, but not in Smath.
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Offline Jean Giraud  
#16 Posted : 29 December 2019 05:32:16(UTC)
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Originally Posted by: jdoe1 Go to Quoted Post
it works on wolfram and symbolab, but not in Smath.

Always plot first ...

Solve -Plot.PNG
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Offline jdoe1  
#17 Posted : 30 December 2019 03:09:09(UTC)
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Originally Posted by: Jean Giraud Go to Quoted Post
Originally Posted by: jdoe1 Go to Quoted Post
it works on wolfram and symbolab, but not in Smath.

Always plot first ...

Solve -Plot.PNG


I somehow missed the option to use the 2nd solve function with root limit, but I didn't need a plot for this, so I used it in one line and everything worked out fine.

I can't click the thank button, so thanks.
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Offline Jean Giraud  
#18 Posted : 30 December 2019 05:01:26(UTC)
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Originally Posted by: jdoe1 Go to Quoted Post
I somehow missed the option to use the 2nd solve function with root limit, but I didn't need a plot for this, so I used it in one line and everything worked out fine.

If you don't plot, you will soon hit the wall.
That will help set the limits.
When applicable, "implicit roots" is often + accurate.

roots.PNG
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