Symbolic solving with defined parameters

[athurin]

Hi,

Sorry if this is a trivial question, but I am only starting to use symbolics, and I haven't found how to do what I want.

If I manipulate equations that are fully symbolic, the results of manipulations are shown in a symbolic way. But if there is one of the symbols that is defined, it is automatically evaluated and replaced by its value in the results. Is it possible to do that ?

Here is an example, calculating the power transfered by sinewave voltage and current with a phase offset. In the first case, the peak voltage is undefined, and I get the expected result : P(phase) = Vpk * Ipk * cos(phase) / 2

In the second case, I define Vpk=100, and the result is P(phase) = 50 * Ipk * cos(phase).

Is there a way to modify the second case, in order to get the same result as the first ?

Thank you very much.

Adrien

[RichardJ · Accepted solution]

You can make it so the symbolic processor does not see the definition. See the attached.

[athurin]

That's awesome. Thank you very much.

[athurin]

Is there a way to clear all symbols in one command, or do I have to list every variable ?

[RichardJ]

You can pass the function a list of variable names, but you do have to list all the variables for which you want the symbolic processor to ignore the numeric assignment.

[athurin]

Thanks