How to Post a Matrix in Precalculus Mathematics

[Mano Jow]

Hello,

I've been trying to use LaTeX to post a matrix but didn't succeed. Here's the code I have:
A = \left(\begin{array}{cc}m&3\\2&1/2\end{array}\right)

But when I put it between [ tex ][ /tex ] (without spaces) I get a '=>'. But here it's working, see $$A = \left(\begin{array}{cc}m&3\\2&1/2\end{array}\right)$$

I'm trying to post it on Precalculus Mathematics sub forum.

What's happening? I've tried this code here and it worked...

Thanks!

 

[Jonathan Scott]

There's a well-known "feature" that when you preview LaTeX you are likely to see cached copies of generated LaTeX images which you used in previous posts. Refreshing the page in the browser or clearing the browser cache usually fixes such problems (but make a copy of the text first in case the process loses what you've already typed in).

 

[Mano Jow]

I see.
But if I post it'll be ok, right?

Thanks!

 

[diazona]

Right. This particular problem only occurs when you're previewing a post.

By the way, it's recommended to do matrices like so:

A = \begin{pmatrix}m&3\\2&1/2\end{pmatrix}

The pmatrix environment puts in the parentheses for you automatically and also fixes some issues with the alignment of the cells.

 

[Mano Jow]

Thanks a lot, really helped!