# Matrices in Latex

• LaTeX

## Main Question or Discussion Point

Hello!

I know how to do a matrice in latex like this:
$\begin{bmatrix} a & b & c \\ d & e & f \\ g & h & i \end{bmatrix}$

How do I write severell matrices on one row like : "matrix_A times another matrix_B = answer "

And how can I label the matrices so I can refer to them later on ?
Thanks

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Hootenanny
Staff Emeritus
Gold Member
Hello!

I know how to do a matrice in latex like this:
$\begin{bmatrix} a & b & c \\ d & e & f \\ g & h & i \end{bmatrix}$

How do I write severell matrices on one row like : "matrix_A times another matrix_B = answer "

And how can I label the matrices so I can refer to them later on ?
Thanks
Like this,

Code:
$\begin{bmatrix} a & b & c \\ d & e & f \\ g & h & i \end{bmatrix} \begin{bmatrix} a & b & c \\ d & e & f \\ g & h & i \end{bmatrix} = \begin{bmatrix} a & b & c \\ d & e & f \\ g & h & i \end{bmatrix}$
With respect to the labelling, do you mean label them by given them a tex label such as \label{matrix1} or simply calling them matrix "A"?

Yes I mean such as \label{matrix1}

Thanks you!

Hootenanny
Staff Emeritus
Gold Member
Yes I mean such as \label{matrix1}

Thanks you!
As far as I'm aware, there are no macros available for numbering terms within a single equation.

The best you could do would be to label the matrices A,B,C using something like \underbrace and then give the equation a label using \label{matrices}. You could then reference the matrices using something of the form:
"see matrix A in \eqref{matrices}"​

If I have the three matrices that you wrote, then I want to refer to all three at the same time, not only the first matrix or the second.
I don´t know how to use \underbrace..

Hootenanny
Staff Emeritus
Gold Member
If I have the three matrices that you wrote, then I want to refer to all three at the same time, not only the first matrix or the second.
That's fine then. Simply give the over all equation a label using \label{matrices} and then you can refer to the equation using \eqref{matrices}.

Yes, kind of.
I have written \label{matrix1} after \end{bmatrix} but it doesnt work, where should I write \label{matrix1} in my code ?

Hootenanny
Staff Emeritus
Gold Member
Yes, kind of.
I have written \label{matrix1} after \end{bmatrix} but it doesnt work, where should I write \label{matrix1} in my code ?
Instead of using the \[ delimiters, which correspond to the displaymath environment, you need to use the equation environment:

Code:
$$[COLOR="Red"]equation goes here[/COLOR] \label{[COLOR="Red"]equation name goes here[/COLOR]}$$
This will then give your equation a number, which can be referred to using the \eqref{equation name goes here} command.

Thank you very much!

Hello!
I have matrices in my LaTex document. LaTex automatically gives order number to all equations, but it doesn’t numerate matrices. Could you help me and say how I could automatically numerate matrices as equations. Beforehand thank you.