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ianlh		#1 Posted : 03 July 2020 15:57:17(UTC)
Rank: Advanced Member Groups: Registered Joined: 18/12/2014(UTC) Posts: 38		Hi, I am a bit stumped with a what is probably a simple problem. I have a root solve in Mathcad that I just cant get to work in Smath, I have tried what I think is correct ways, but still not working, see below for example: I have also tried stripping out the units, but still no luck Hoping someone has the simple solution. Ian
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Jean Giraud		#2 Posted : 03 July 2020 19:05:46(UTC)
Rank: Guest Groups: Registered Joined: 04/07/2015(UTC) Posts: 6,866 Was thanked: 981 time(s) in 809 post(s)		Always plot before solving ! Solve UNK.sm (213kb) downloaded 24 time(s).
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overlord		#3 Posted : 04 July 2020 01:03:05(UTC)
Rank: Advanced Member Groups: Registered Joined: 23/07/2013(UTC) Posts: 1,126 Was thanked: 507 time(s) in 338 post(s)		Originally Posted by: ianlh Hi, I am a bit stumped with a what is probably a simple problem. I have a root solve in Mathcad that I just cant get to work in Smath, I have tried what I think is correct ways, but still not working, see below for example: I have also tried stripping out the units, but still no luck Hoping someone has the simple solution. Ian I have tried on Mathcad and it didn't work either. Obviously there is a mistake with the formula. You can't add kg*N/s^2 with kg/s^2. Units mismatch. But if you divide the givens you can get the correct answer. If this approach is true of course since we don't have more information. Regards.
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overlord		#4 Posted : 04 July 2020 03:37:54(UTC)
Rank: Advanced Member Groups: Registered Joined: 23/07/2013(UTC) Posts: 1,126 Was thanked: 507 time(s) in 338 post(s)		Jean, direct question; Are you being sarcastic about my comment?
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Jean Giraud		#5 Posted : 04 July 2020 15:14:08(UTC)
Rank: Guest Groups: Registered Joined: 04/07/2015(UTC) Posts: 6,866 Was thanked: 981 time(s) in 809 post(s)		Originally Posted by: overlord Jean, direct question; Are you being sarcastic about my comment? I have removed my comment. In my times, maths were unitless working well. Now, put units in maths ... red results.
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Razonar		#6 Posted : 04 July 2020 21:00:31(UTC)
Rank: Advanced Member Groups: Registered Joined: 28/08/2014(UTC) Posts: 1,356 Was thanked: 815 time(s) in 516 post(s)		Originally Posted by: ianlh Hi, I am a bit stumped with a what is probably a simple problem. I have a root solve in Mathcad that I just cant get to work in Smath, I have tried what I think is correct ways, but still not working, see below for example: I have also tried stripping out the units, but still no luck Hoping someone has the simple solution. Ian Hi. Your setup is correct for Mathcad, but unfortunately SMath's solvers do not works like in Mathcad, and needs some help for use units. SolveWithUnits.sm (17kb) downloaded 16 time(s). Best regards. Alvaro Edited by user 04 July 2020 21:02:30(UTC)  | Reason: Not specified
3 users thanked Razonar for this useful post.		on 04/07/2020(UTC),  on 05/07/2020(UTC),  on 05/07/2020(UTC)
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overlord		#7 Posted : 04 July 2020 22:16:18(UTC)
Rank: Advanced Member Groups: Registered Joined: 23/07/2013(UTC) Posts: 1,126 Was thanked: 507 time(s) in 338 post(s)		I have checked with changing all inputs; somehow the two formula give same calculation every time. Regards
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ianlh		#8 Posted : 05 July 2020 13:29:58(UTC)
Rank: Advanced Member Groups: Registered Joined: 18/12/2014(UTC) Posts: 38		Hi All, Thanks for the help with this, I like the solution by Alvaro, seems the most elegant.
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Jean Giraud		#9 Posted : 05 July 2020 16:14:25(UTC)
Rank: Guest Groups: Registered Joined: 04/07/2015(UTC) Posts: 6,866 Was thanked: 981 time(s) in 809 post(s)		Unless you don't agree with yourself, solving SQRT implies the two solutions. Presumably delimiting the range of the solvable project.
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Razonar		#10 Posted : 05 July 2020 20:30:31(UTC)
Rank: Advanced Member Groups: Registered Joined: 28/08/2014(UTC) Posts: 1,356 Was thanked: 815 time(s) in 516 post(s)		Originally Posted by: overlord I have checked with changing all inputs; somehow the two formula give same calculation every time. Regards Hi Overlord. You found an amazing symbolic solution for the original problem. I can't explain why, but my guess is that f1, f2 and f3 must to be related with the directors cosines or something like that. Maple shows that your solution and the symbolic solution are the same, but must to force some "not-always-true" reductions in maple, with the command "maple(simplify(expression,symbolic))" SolveWithUnits overlord.sm (36kb) downloaded 11 time(s). SolveWithUnits overlord.pdf (98kb) downloaded 17 time(s). Best regards. Alvaro.
1 user thanked Razonar for this useful post.		on 15/07/2020(UTC)
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mkraska		#11 Posted : 06 July 2020 10:43:09(UTC)
Rank: Advanced Member Groups: Registered Joined: 15/04/2012(UTC) Posts: 1,985 Was thanked: 1124 time(s) in 721 post(s)		Once Maxima and the Maxima plugin are installed, you have a symbolic solver without unit issues. solve.sm (10kb) downloaded 15 time(s).
		Martin Kraska Pre-configured portable distribution of SMath Studio: https://smath.com/wiki/SMath_with_Plugins.ashx
1 user thanked mkraska for this useful post.		on 06/07/2020(UTC)
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