How to create a matrix with variables?

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.

Risposte (2)

Walter Roberson
Walter Roberson il 26 Gen 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 Commenti

Really sorry for the confusion. Not sure why I used the term 'plot' rather than 'create'. What I am looking to do is to create this matrix. I will edit my original post now to avoid confusion.
Could you expand on the symbolic toolkit part?
Thanks :)
Is dt/Vr intended to represent a derivative? If so is Vr a distinct variable? Are Act or Fr or Fc functions of t and or/ Vr and Vc ?
BZ0892
BZ0892 il 28 Gen 2016
Modificato: BZ0892 il 28 Gen 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.
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]

Accedi per commentare.

Richiesto:

il 26 Gen 2016

Commentato:

il 29 Gen 2016

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