differential equations

differential equations - solve differential equations - Сообщения

#1 Опубликовано: 21.12.2019 07:50:00
Ale16595

Ale16595

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Hello everyone! I wanted to know if it is possible to solve differential equations with Smath Studio. in particular I would be interested in solving ordinary nonlinear second order differential equations.
Thanks in advance.
#2 Опубликовано: 21.12.2019 08:47:59
Martin Kraska

Martin Kraska

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In the interactive handbook (see Tools> Plugins> Interactive books (switch to online gallery)) there is a section

Mathematics> Ordinary Differential Equations.

In the examples subsection you find a variety of non-linear ODEs with numerical and symbolic solutions (based on Maxima plugin).
Martin Kraska Pre-configured portable distribution of SMath Studio: https://en.smath.info/wiki/SMath%20with%20Plugins.ashx
#3 Опубликовано: 21.12.2019 09:11:51
Ale16595

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Thank you very much.
Cheers
#4 Опубликовано: 21.12.2019 11:17:44
Jean Giraud

Jean Giraud

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Hello everyone! I wanted to know if it is possible to solve differential equations with Smath Studio. in particular I would be interested in solving ordinary nonlinear second order differential equations.
Thanks in advance.


Please: attach DE.

#5 Опубликовано: 21.12.2019 14:18:45
Jean Giraud

Jean Giraud

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... here is an example:

ODE Lorenz Attractor Publish.sm (15 КиБ) скачан 139 раз(а).
#6 Опубликовано: 22.12.2019 09:21:49
Ale16595

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Hi, the differential equations that i should solve are like the ones in the picture:

ode.png

here is also the .sm file… Documento2 DE.sm (21 КиБ) скачан 71 раз(а).
#7 Опубликовано: 22.12.2019 10:20:10
Jean Giraud

Jean Giraud

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here is also the .sm file


φ''(t) ... is not defined

Documento2 DE.sm (25 КиБ) скачан 81 раз(а).

Alvaro has done lot of work on that one, few days ago
it was about tangent, curvature ... As it look: same system.
#8 Опубликовано: 22.12.2019 10:37:33
Jean Giraud

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... revisit your original document 11 days ago.
revisit Alvaro reply.

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#9 Опубликовано: 22.12.2019 14:03:53
Ale16595

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Yes, the problem is the same as a few days ago. This time, however, I had to modify it slightly and I must be able to derive the psi and phi functions using the differential equations in the figure.
#10 Опубликовано: 22.12.2019 17:11:17
Jean Giraud

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Hi, the differential equations that i should solve are like the ones in the picture:


... still undefined wrt φ'(t)
If you can help more: please re-post this document
so to avoid refactoring.
If you have the original work out and solution it
might help converting to Smath

Documento2 DE [explain more].sm (33 КиБ) скачан 68 раз(а).

#11 Опубликовано: 23.12.2019 12:12:02
Ale16595

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Why should i define the phi function?
Should I get it by solving the differential equation, or am I wrong?
#12 Опубликовано: 23.12.2019 14:46:23
Jean Giraud

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Why should i define the phi function?
Should I get it by solving the differential equation, or am I wrong?


You are right, after the numerical ODE solver you will have
the manipulate the solution depending upon sin/cos
The 2nd term is not a simple coefficient. That induces FinDiff.
So, you have nothing from source ? Pure invention top/bottom.

Documento2 DE [explain more].sm (66 КиБ) скачан 50 раз(а).
#13 Опубликовано: 23.12.2019 18:03:01
Jean Giraud

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... a short revisit.

ODE Compendium_1.sm (154 КиБ) скачан 84 раз(а).
#14 Опубликовано: 23.12.2019 23:01:55
Jean Giraud

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... that's as far as I can make this project respond.
Not enough insight to go further.

Page57 ODE.sm (12 КиБ) скачан 77 раз(а).
#15 Опубликовано: 24.12.2019 09:02:40
Jean Giraud

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... that's as far as I can make this project respond.
Not enough insight to go further.


... your original parameters send the DE solutions in the zillion domain.
Zillion domain is no maths, something does not cut the mustard in there.
Better sanity with other CAS ...

Documento2 DE [explain more].sm (45 КиБ) скачан 57 раз(а).



#16 Опубликовано: 24.12.2019 13:12:05
Ale16595

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Hi, thanks for the help and patience.
This is a task I have been assigned and I am not following any source.
If it can be helpful to derive the function phi, I know that:
-for t=0, phi=0
-for t=6.187, phi=0.867 and phi'=0
#17 Опубликовано: 24.12.2019 23:31:28
Jean Giraud

Jean Giraud

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Hi, thanks for the help and patience.
This is a task I have been assigned and I am not following any source.
If it can be helpful to derive the function phi, I know that:
-for t=0, phi=0
-for t=6.187, phi=0.867 and phi'=0


=================================

-for t=6.187, phi=0.867 and phi'=0
we have that from freaking p1 parameter
and obviously phi'=0
for t=0, phi=0 ...that can't be
whereas the system starts @ IC 0.005

1. Make sure the DE as proposed is OK
2. What software the presumed assignment is based on ?
... it could be wrong from the onset !!!

Documento2 DE [explain more].sm (48 КиБ) скачан 49 раз(а).

#18 Опубликовано: 25.12.2019 07:19:07
Ale16595

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I modified some values ​​and a relationship because I noticed an error.
The differential equation, on the other hand, should be correct because it comes out of the physical problem it is trying to solve.
As for the assignment of values, I always get them from the physical system knowing more or less the trend of the phi function to be obtained.

If it can help the progress of this function it is the following:
-The phi function starts from 0.147 for t = 0, grows up to a maximum equal to 0.867 for t = 6.187 and finally decreases
-The function phi' instead starts from a value 0 for t = 0, in the interval between t = 0 and t = 6.187 reaches a maximum and then returns to 0 when t = 6.187


Then I would have a question, why does phi' appear in the differential equation and not phi?
ode1.png
#19 Опубликовано: 25.12.2019 10:21:29
Jean Giraud

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Then I would have a question, why does phi' appear in the differential equation and not phi?


Good question: you are the Man who proposed the DE phi'.
For your above attempted explanation, you are just presuming.
1. Setup the DE ... as per the assignment
2. Confirm the reference solver software the Originator is using.
Will be back while waiting.
The project is pure blue sky ... sending a fly to Cirus ?
#20 Опубликовано: 26.12.2019 09:51:56
Jean Giraud

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Does the CannonBall project suggest something ?

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