Mathematica Problem in NDSolve in mathematica

[yashar]

i want to solve a large system of coupled differential equations but i get this error

NDSolve::nlnum:

i attach the notebook in zip format.

what is the problem?

thanks

 

[Bill Simpson]

Search your notebook for
ro24 and ro44
and see if you really meant
rod24 and rod44

Just a guess

 

[yashar]

thanks
that was amazing!
how you guess that?

 

[Bill Simpson]

Actually I did not just guess that. If I had guessed that it would have been amazing. Now you have to think about how I was able to find those two in the 400+ equations that you have there. And how you might more likely avoid problems similar to this in the future.

 

[yashar]

i can not understand how did you do that.
please tell me how?

 

[Bill Simpson]

http://stackoverflow.com/questions/...iables-functions-in-a-notebook-in-mathematica

is one method to do this particular task.

Developing the ability to find explanations for puzzling Mathematica behavior is extremely important for every Mathematica user. I really suggest that you try to figure out how you could have found this yourself. Then see if you can generalize that method to help you be able to find the answer to the next question you find.