Newbie problem solving system of 3 ODE's

[ME_10255445]

Hello guys,

I'm a newbie and I want to ask how to read these mcdx files with MathCad.

I can't get them open in MathCad..

Any idea?

Original Post

[Werner_E]

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@ME_10255445 wrote:

Hallo guys,

I'm a newbie and I want to ask how to read these mcdx files with MathCad.

I can't get them open in MathCad..

Any idea?

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mcdx is the format of Mathcad Prime.

There is no way I am aware of to convert such files so they could be opened with real Mathcad (Mathcad up to version 15).

Only way is to download a copy of Prime (it works as a full trial for a month and then falls back to a limited "Express" mode, which is still able to open all Prime files and show the calculation results) to open the mcdx file and retype the sheet in real Mathcad

[VladimirN]

Mathcad Prime 8.0:

https://www.mathcad.com/en/try-and-buy/mathcad-express-free-download/install

https://free-dl.ptc.com/install/pim_installmgr_mathcad.exe

[VladimirN]

Mathcad Prime 8.0:

https://www.mathcad.com/en/try-and-buy/mathcad-express-free-download/install

https://free-dl.ptc.com/install/pim_installmgr_mathcad.exe

[ME_10255445]

I have some issues on my laptop which why Ican;t install it but thanks anyway

[Werner_E · Accepted solution]

Just uploaded a screenshot of the sheet you asked for in the other thread

https://community.ptc.com/t5/PTC-Mathcad/Newbie-problem-solving-system-of-3-ODE-s/m-p/795362/highlight/true#M201044

[ME_10255445]

I saw it, thx 

[Werner_E]

I fear that it will not help you with the problem you posted here https://community.ptc.com/t5/PTC-Mathcad/Multiple-ODE-s-in-MathCad/td-p/785905/jump-to/first-unread-message

I guess that Matlab has more and more powerful functions/algorithms.

With Mathcad it was always difficult to solve boundary problems where the ICs referred to different positions (in your case 0, s1 and L)
Mathcad provides functions like sbval and bvalfit to calculate(guess) the missing inital values, but I lack any experience in using those functions.

[ME_10255445]

Thx for your input.

But is there an idea to couple all the boundary/matching conditions to a certain (same) time value, and specify their exact values then without guessing?

If u understand what I mean..

I hope I expressed myself clear 🙂

Thx in advance 

[Werner_E]

Looking in your sheet its clear to me what you are trying to achieve but actually I can see no way to find initial conditions all referring to x=0 or the like. I guess that especially the conditions that both U and W should have the same (but unknown) first and second derivative at x=s1 are main part of the problem.
Actually I have no idea how to come closer to a solution than Alan did and thats also the reason I did not post in the main thread just to clutter it with a meaningless "I also don't know how to do it" 😉
Alan isn't here on a daily basis but drops by from time to time. Maybe he can come up with an idea how to improve his partial solution.

[ME_10255445]

I understand..

Thx anyway mate..

Let's see if Alan can do anything about it.

I will keep digging aswell.