How to create a matrix with variables?

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BZ0892
BZ0892 am 26 Jan. 2016
Kommentiert: Walter Roberson am 29 Jan. 2016
Hello,
I am kind of new to Matlab so the questions I will ask probably sound a bit basic. Anyways, here goes:
I want to create the matrix below which has both constants and variables. How can I do this? I know how to create a normal matrix (e.g. B = [1 0 2; 3 4 5; 0 2 3] but I don't know how to create matrices with variables in them?
I tried to type the matrix in as is shown above but it doesn't seem to work. I'm pretty sure I should be following some sort of method but I have no clue.
I want to have the ability to assign different values to the variables at later stages as well.

Antworten (2)

Azzi Abdelmalek
Azzi Abdelmalek am 26 Jan. 2016
v={0 1;'act*fr' 'y'}

Walter Roberson
Walter Roberson am 26 Jan. 2016
It is not possible to plot a matrix that has unassigned variables in it. If you have the symbolic toolkit, it is possible to create such a matrix, but in order to plot you need to substitute particular numeric values.
The matrix looks to me to be a transformation matrix for 3D points. You do not plot transformation matrices themselves: you plot the results of transforming something.
  4 Kommentare
BZ0892
BZ0892 am 28 Jan. 2016
Bearbeitet: BZ0892 am 28 Jan. 2016
Apart from element a31, all the elements are constants that I've been given. Element a31 can vary since the ''Act'' term can vary. I understand that I can just enter the constants instead for the other elements, but for now I'd like to enter the elements so it looks like the image I posted.
Thanks!
EDIT: I'd like to add that in element a44, there should be no ''/'' sign. That is a mistake. It should be just 1-Fc*dt/Vc.
Walter Roberson
Walter Roberson am 29 Jan. 2016
Assign values to dt Fr Fc Vc Vr
then
syms Act
A = [1 0 0 0; 0 1 0 0; Act*Fr*dt/Vr 0 ... and the rest of the terms]

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