1. May 21, 2012

### applechu

Hi:
I am a newbie to this forum, and I don't know how to
use the text editor correctly. If I hope to write an 3x3 matrices,
how to key in it correctly in this thread.
and furthermore, if there any manual about the editor, thanks a lot.

2. May 21, 2012

### Staff: Mentor

3. May 21, 2012

### applechu

I have tried a example as following, but still not work:
\begin{matrix}
1 & 1 & -1\\
1 & -1 & 1\\
1 & 1 & 1
\end{matrix}

is there any other method, thanks

4. May 21, 2012

### spamiam

That looks pretty good! If you want round parentheses around your matrix use pmatrix:
$$\begin{pmatrix} 1 & 1 & -1\\ 1 & -1 & 1\\ 1 & 1 & 1 \end{pmatrix}$$
and for square brackets use bmatrix:
$$\begin{bmatrix} 1 & 1 & -1\\ 1 & -1 & 1\\ 1 & 1 & 1 \end{bmatrix}$$.

Also, surround your LaTeX with either ## or  (click 'Quote' to check out my example).

5. May 21, 2012

thanks