a name is required here

[JPark61]

help please...

[LucMeekes]

You should NOT use global assignments ( = ), but boolean equality to define the equations in your solve block. Type [CTRL =] to get those. They show as a bold equals sign ( = ).

Success!
Luc

[Werner_E]

Additional remarks:

1) You have to only use the function names without the argument parenthesis (use "C" and not "C(t)")

2) You have only 5 equations but 6 functions to solve for.

[JPark61]

I attached new pic.

can you solve it please..

[-MFra-]

Hi,

[JPark61]

Thank you, can you attached file please?

[JPark61]

and why is f(t):0.5*cosh(t)??

[-MFra-]

Hi,

you should provide the f (t); what I chose is a convenience function. I do not believe that Mathcad is able to determine f (t) as an unknown knowing only its initial condition.

[JPark61]

thank you 

but the answer is below the attached file.

Do you know why?

please..

[-MFra-]

Hi,

If there were a further differential equation in f(t), things would change. See the following example:

[JPark61]

can you send me a file?

[-MFra-]

I've attached the file.

[LucMeekes]

That very blurry picture shows a graph with only 4 traces. That's 4 functions, not 6.

Are you sure you have entered the complete set of ODE's, required for solving the 6 functions that you are trying to find?

Luc

[JPark61]

I attached new pic.

can you solve it please..

[LucMeekes · Accepted solution]

Story continues here: https://community.ptc.com/t5/PTC-Mathcad/too-many-initial-conditions/m-p/637903#M188074