7-Bedrock

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differential equation solver

Forum|Forum|10 years ago
August 30, 2015
3 replies
6760 views

I’ve used mathcad years ago, but I have not used it much since ptc switched it to prime.

I’m trying to solve partial differential equation, shown below:

After some simplification, the equation will be this:

I can write Tm as a 3rd order polynomial trend line.

finally after some reorganization the final equation:

I'd like to plot V(t) vs. t

Am I on the right path? Last time I solved differential equations was 20 years ago, and I was not good at it I still have some weak memories of differential equation solving when both the function and the first derivative are in the same equation. I tried to solve this in excel with numerical differentiation but that one did not yielded good results either.

Any help if greatly appreciated. thank you!

Calculus_Derivatives

Best answer by VladimirN

Please find in attachment the contents of this Mathcad Prime worksheet in PDF file format.

24-Ruby IV

We can solve numerically some partial diff. equation in Mathcad 15 with the pdesolve function.

But in Prime there is no this function.

Sorry.

Are you sure that your DE is the partial DE not ODE?

24-Ruby IV

Sorry.

Partial=one?

If your ODE is y'(t)=a+b*y(t)^2 you can solve it symbolically..

Author

7-Bedrock

Valery, you're right. I believe too, it's a ODE in the form you've mentioned. I'm still not sure why mathcad does not like the notation this way.

24-Ruby IV

Use not = but ctrl+=

One example

Author

7-Bedrock

Valery, I tried the ctrl+= but it did not work. I also tried the example you've shown and it won't even plot the graph.

25-Diamond I

Re ist the name of a built-in function, therefore the error.

Either define an appropriate range variable Re or use a different variable name - just in the plot, you can leave Re in the function definition.

WE