Matrix Factorization.

[lvl107]

Hello, Everyone.

Thanks in advance for your time and help.

Best Regards.

[Werner_E]

You sure can't multiply a 3x3 by a 4x4 matrix! To obtain a 3x4 matrix you have to multiply a 3 x n matrix with a n x 4 matrix.

[Werner_E]

Why don't you simply use normal matrix arithmetic to get the "factorization" you need - if you need the result at all. You have different ways to do so:

[lvl107]

And a similar query :

Thanks in advance for your time and help.

Best Regards.

[Werner_E]

Why do you want to solve for 21 variables when you only have 12 equations???????????????

The way to do it is exactly the same as I have shown above (2nd), just do it symbolically. the 3x3 matrix can be anything as long as the matrix isn't singular.

[lvl107]

I greatly appreciate your time and help to my questions, Werner. And I have a different question and I have observed the following :

I need help with the reason : the equation, the above ( red one ) , was not solved for 14th unknown ( X[13 ) .

Thanks again.

Best Regards.

[Werner_E]

I need help with the reason : the equation, the above ( red one ) , was not solved for 14th unknown ( X[13 ) .

As already described above - you only have 12 equations but 14 variables to solve for. Mathcads solve does not like over or undedetermined systems.

[lvl107]

Werner,

It seems that " no solve for 14th unknown X[13 " :

Thanks again.

Best Regards.

[Werner_E]

Yes, Mathcad's symbolics could find a/the solution in this case, but it doesn't. Seems its not perfect 😉