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ptc-57822981-Visitor
1-Visitor
April 22, 2014
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symbolic solve second order differential equations

  • April 22, 2014
  • 1 reply
  • 4861 views

Hi all,

I have a system of two coupled second order ODE equations that I would like to solve symbolically. I have checked Mathcad' quicksheet and browsed this forum, but to no avail. Most of the information I find is on numeric solvers. At first glance I though it could be done in matrix form, but then I don't know how to go about.

Is this at all possible? Can someone lend me a hand on this?

Many thanks,

Newin

Best answer by AlanStevens

Your original Laplace_test contains two dN1's where it should contain one dN1 and one dN2 - see attached.

Alan

1 reply

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AlanStevens19-Tanzanite
19-Tanzanite
April 22, 2014

Mathcad won't solve ODEs analytically in general. You could obtain the Laplace transformed solutions in the s-domain ok, but I think the result is too complicated to stand any chance of being inverse transformed back to the time domain analytically.

Is there a good reason for wanting a symbolicl, rather than a numerical solution?

Alan

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ptc-57822981-VisitorAuthor
1-Visitor
April 22, 2014

Hi Alan,

It is just for my own preference that I like to see how the solution changes as I modify the terms in the coupled equations, i.e. adding external forces, or removing some of the terms.

I am working now to solve it numerically and will report back how it goes.

Newin

P
ptc-57822981-VisitorAuthor
1-Visitor
April 22, 2014

Hi Alan,

I have started with the numeric solver, but it is far from complete. Attached is the worksheet, where I include alongside the code some explanation of what I need to get done. As I said, this is far from complete and I am working on it, but just thought that you could have a look if you have the time.

The tricky parts for me is firstly, the coupled equation that I need to get two uncoupled equations and then solve each of them separately, and secondly, that I would like to do some further processing on the results, such as integration or plotting the results against some other variables that is not the variable used in the derivatives.

Any help would be appreciated!

Newin

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