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ptc-51250911-Visitor
1-Visitor
June 8, 2013
Question

Defining matrice members as variables

So i kinda have the same problem in these 2 problems.

First one is:

Untitled2.png

In whiich i have to find the values of A and B members.

And the second one is:

Untitled3.png

In which 3 of the members have the value of 0, 3 of 1 , 2 of 2 and 1 of 3.

In both of those i am having trouble in defining the matrices and using those matrices to find solutions.

Any help is welcome.

5 replies

Werner_E
Werner_E25-Diamond I
25-Diamond I
June 8, 2013

Mathcad won't do it that easy out of the box, especially the second one, but it can help alot in solving the task. For example the second one:

matrixEqu2.png

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AndyWesterman12-Amethyst
12-Amethyst
June 10, 2013

As with the ideas for the second problem from Werner, Yon can use the symbolic engine to provide some help with understanding the matrix multiplication:

Capture.PNG

But in this case a solve block will produce an answer:

Capture.PNG

Note that I have included conditions for all the zero elements in the arrays.

If these are omitted the result could include non-zero elements here.

There are also 4 highlighted equations (currently disabled).

Your initial information has 10 unknowns, but the matrix equality only provides a maximum of 16 equations - so this is only 1 of many solutions.

Adding / changing these 4 equations or the initial guess values will give alternate answers to the problem.

Regards

Andy

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Werner_E
Werner_E25-Diamond I
25-Diamond I
June 10, 2013

You changed the definition of matrix B.

With the original definition we get a pretty integer result:

MatrEqu1.png

BTW, with your changed information you have 20 unknowns and only 16 equations.

The original task has 16 unknown and 16 equations.

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