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L
lvl10720-Turquoise
20-Turquoise
January 6, 2013
Question

Equation Solving 2.

  • January 6, 2013
  • 4 replies
  • 4903 views

Hello, Everyone.

My question :

Built-in+function+solve%2C_.PNG

My question is : Is there an other built-in function for this ?

Thanks in advance for your time and help.

Best Regards.

4 replies

J
jkowalski1-Visitor
1-Visitor
January 6, 2013

See.

I have a problem with 5 parts of the equation.


http://communities.ptc.com/message/56576#56576

W
Werner_E25-Diamond I
25-Diamond I
January 6, 2013

Loi Le schrieb:

My question is : Is there an other built-in function for this ?

Yes, you could use a solve block without guess values and evaluate it symbolically. The result however will be the same. The expression for M is too large for Mathcad to display. See attached file.

But I think that you are not really interested in looking at an expression that big - you'd rather want to use it (for whatever). And you can do this in any way you would do if you could see it,

You have to assign the evaluation to a variable, a vector (or Matrix, if there are more than one solution) and may symbolically show the single elements. All but the solution for M will display.

See the attached file for more information.

WE

Built-In1.png

J
jkowalski1-Visitor
1-Visitor
January 7, 2013

I solved problem see attached file.

W
Werner_E25-Diamond I
25-Diamond I
January 7, 2013

Nice idea to use substitution to shorten the expression.

Maybe it would be more comfortable to let Mathcad do the work.

On the other side nothing would be comfortable with that sort of expressions, I suppose. So I have chosen a more simpler example to demonstrate. You may apply the same method using the solve block, of course.

subst.png

I can not think of any way to avoid having to retype the substitution (third expression, resubstitution)

WE

L
lvl10720-TurquoiseAuthor
20-Turquoise
January 8, 2013

Hello Everyone again,

And I have a related question :

Built-in function solve3.PNG

Thanks in advance for your time and help.

Best Regards.

W
Werner_E25-Diamond I
25-Diamond I
January 8, 2013

Loi Le schrieb:

Hello Everyone again,

And I have a related question :

Built-in+function+solve3.PNG

Thanks in advance for your time and help.

Best Regards.

I'm too lazy to try it myself. Substitution, as Jan showed, did not work??

W
Werner_E25-Diamond I
25-Diamond I
January 8, 2013

OK Loi,

see attached what I meant by using vectors. I think these are the equations you are dealing with.

Its almost automatic, but I dont know what can be done to automate the vector at the solve command.

You may have to delete the "simplify" at the solve command when increasing N.

Perhaps someone else has an idea - see screenshots below or attached worksheet.

You will run into the same problems with Mathcad not being able to show the result.

You may work with an automatic substitution (a[j] - a[n]) --> A[10*j+n] or something similar to make the expressions shorter - see attached sheet.

Built1.png

Does anyone know why the follwing two expressions don't work and how one could make the solve to work withou manual intervention for arbitrary N?

Built2.png Built3.png

J
jkowalski1-Visitor
1-Visitor
January 8, 2013

The solution your problem is beyond my capabilities. Mathcad studying only for 3 months.Therefore, you can not help

PS. (google translator is suc*s)

W
Werner_E25-Diamond I
25-Diamond I
January 9, 2013

I'm not sure if a solution to this problem exists. The coexistence of the numeric and symbolic processor is not always smooth and peaceful.

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