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ND_106477341-Visitor
1-Visitor
Apr 14, 2023 5:39 PM UTC
Solved

odesolve: fewer than 3 arguments

Hello,

 

I have been trying to solve this DAE system using MathCad Express Prime 9.0, but I have tried several things and I won't run. Can someone please take it a look and let me know why it does not work?

 

Thank you very much.

 

 

 

LucMeekesAnswer
23-Emerald V
Apr 15, 2023 3:51 PM UTC

Welcome to this forum, Nathan.

This calculation:

LucMeekes_0-1681573214697.png

Should not be in the Constraints section of the solve block. It doesn't contain any of the functions for the set of ODE:

LucMeekes_1-1681573363080.png

The five remaining equations leave

LucMeekes_2-1681573453148.png

as only implicitly defined.

Not that it helps. I still get the error message that "odesolve has fewer than 3 arguments" which is weird because the third argument of odesolve is optional, and adding a third argument doesn't change the error message.

Continuing...

 

Luc

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2 replies

LucMeekes23-Emerald VAnswer
23-Emerald V
Apr 15, 2023 3:51 PM UTC

Welcome to this forum, Nathan.

This calculation:

LucMeekes_0-1681573214697.png

Should not be in the Constraints section of the solve block. It doesn't contain any of the functions for the set of ODE:

LucMeekes_1-1681573363080.png

The five remaining equations leave

LucMeekes_2-1681573453148.png

as only implicitly defined.

Not that it helps. I still get the error message that "odesolve has fewer than 3 arguments" which is weird because the third argument of odesolve is optional, and adding a third argument doesn't change the error message.

Continuing...

 

Luc

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    Werner_E
    Werner_E25-Diamond I
    25-Diamond I
    Apr 15, 2023 4:37 PM UTC

    I still get the error message that "odesolve has fewer than 3 arguments" which is weird because the third argument of odesolve is optional, and adding a third argument doesn't change the error message.

     

    You get a different error message if you put the assignments at the top of the solve outside and in front of the block (where they belong to).
    Only five equations for six functions and no derivatives for three of those functions, so no ODE.

    We may also eliminate all three "r" functions leaving a system in x1, x2 and T, but now it can be clearly seen that one equation is missing - only two equations for three function.

    Werner_E_0-1681577383162.png

     

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