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A
Anonymous
November 17, 2010
Solved

MathCAD ODE Problem

  • November 17, 2010
  • 2 replies
  • 5587 views

I'm working on what I though to be an easy problem to predict temperature of a tank as a function of time. The tank contains water and some solid pellets, each containing solvent. The tank is heated with a steady source of energy. The solvent is boiled off. The solvent fraction of the liquid, pellets, and evolving vapor are all known and are each a function of temperature.

Odesolve seems to work but when I attempt to get an answer from the generated function or generate a graph, an error "This value must be a scalar" is reported.

It really has me confused. Obviously I don't use Odesolve often enough. Any help would be appreciated.

Best regards,

Best answer by AlanStevens

See attached.

Alan

2 replies

A
AlanStevens19-TanzaniteAnswer
19-Tanzanite
November 18, 2010

See attached.

Alan

A
Anonymous
November 18, 2010

Ever so clever. Wish my brain worked like that.

Thanks so much!

P
PhilipOakley1-Visitor
1-Visitor
November 18, 2010

Dale,

The first odesolve parameter (tau) should be the function name alone without the parameters. (a little detail hidden in the help file)

Then let Alan's solution speak for itself....

Philip

A
AlanStevens19-Tanzanite
19-Tanzanite
November 18, 2010

Philip Oakley wrote:

Dale,

The first odesolve parameter (tau) should be the function name alone without the parameters. (a little detail hidden in the help file)

Philip

Note that this is only needed when solving a system of ODEs. For a single ODE it isn't used.

Alan

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