Problem for Symbolics block equation by using Find

[jzhang-10-11-121]

Hi,

I would really appreciate if you can help me on this symbolics equation!! Thanks!!

There is a problem when I use   keyword "Find" to solve the symbolics equation .

It actually pretty simple equation: I have 6 variables and 6 equation, and I want to get the the unknown parameters symbolics expression.

[Werner_E]

Please open a discussion if you have a question and don't create a document.

http://communities.ptc.com/community/mathcad?view=discussions

One reason is that we cannot attach worksheets in the comments we give here. Second reason is we can much harder keep track of a discussion as those comments won't show up as new postings.

1) You have to use the literal index for your variables and not the vector index (use R.s instead of R[s)

2) Solve for ALL 6 unknowns, not just for the two of interest

Are you really in need for a symbolic solution or would a numeric one suffice (depending on the values of the known - you alread have setup a function M() anyway)

If symbolics is mandatory you may also consider trying the symbolic solve command instead of a symbolic evaluation of a solve bock.

[Werner_E]

Another point: Your six equations are not independent. The first five can be reduced to: I.qs^2+I.ds^2=0, while the sixth says I.qs^2+I.ds^2=I.s.  I.s can be any given value and so you would get a "solution not found" from Mathcad. Check your formulas!

[jzhang-10-11-121]

Thanks so much for your input. I've repost in the following link:

http://communities.ptc.com/thread/54023

1). You're right about literal index use R.s . I've corrected on the update file.

2). About "The first five can be reduced to: I.qs^2+I.ds^2=0", unfornately, I didn't get the same result as yours. I checked formula, which is correct. And I actually manually calculate those equation, but I want to verify my result in MathCAD. Could you explain me about how you get the result on MathCAD file in details?

Thanks so much~~!