Skip to main content
A
AB_110357011-Visitor
1-Visitor
July 19, 2025
Question

Defining a time-dependant function

  • July 19, 2025
  • 1 reply
  • 1496 views

Hello,

I am a beginner in Mathcad using Prime 10.0.0.0 Educational Edition.

 

I want to calculate the kinetic energy of a mechanical system so I have to define a time-dependant function, but I'm not able to do this.

 

I want to calculate the symbolic expression.

 

I write the function as alpha(t):=[function including t as time variable] and I don't get any errors, when I try to use this function later I get the error "The variable is undefined. Check that the label is set properly".

I don't know if I'm using the time variable t wrong or it's an algebra problem.

Any ideas?

 

Thank you,

Andrea

1 reply

W
Werner_E25-Diamond I
25-Diamond I
July 19, 2025

1) What you define with T is again a function in t, so you have to write T(t):=...

 

2) Even if you do so you will get an error if you try to evaluate function T for a specific time value

Werner_E_0-1752955498310.png

Reason are your definitions of function phi1 and phi2

Werner_E_1-1752955571465.png

These definitions don't make sense. Its kind of an infinite recursion.

What did you intend with that definition? What function result value do you expect from, for example, phi1 (2 s) = ???

 

    A
    AB_108608371-Visitor
    1-Visitor
    July 20, 2025

    Oh of curse, by defining it like this T should be T(t), you're right.

     

    I wanted to tell Mathcad that phi1 and phi2 are unknown values, looking around the web I found that should be a viable method, but I am a bit confused.

    I guess this isn't the right way, it's basically the core of my post, what would you advice?

     

    Thank you for the response,

    Andrea

     

    W
    Werner_E25-Diamond I
    25-Diamond I
    July 20, 2025

    If phi1 & 2 are 'unknown' variables or functions, then don't define them. But of course you can't expect any numerical result when evaluating functions depending on these unknowns.

    Its absolutely unclear to me what you actually want to achieve.

    Terms & ConditionsCookie settingsAccessibility statement