Formatting within a matrix...

Starx · **Posted:** Wed, 8 Oct 2008 17:18:56 UTC

I'm using the following code:

Code:

\[L = \begin{bmatrix}
1 & -1 & 0 & 0\\
-1 & 3 & -1 & -1\\
0 & -1 & 2 & -1\\
0 & -1 & -1 & 2
\end{bmatrix}\]

to create this:

$L = \begin{bmatrix} 1 & -1 & 0 & 0\\ -1 & 3 & -1 & -1\\ 0 & -1 & 2 & -1\\ 0 & -1 & -1 & 2 \end{bmatrix}$

But I don't like how the -1's don't line up. Is there a way I can make it right justified?

Opalg · **Posted:** Wed, 8 Oct 2008 17:33:35 UTC

This is a laborious way to do it, but you can put a phantom minus sign in front of all the non-negative elements so that they line up.

Code:

\[L = \begin{bmatrix}
\phantom{-}1 & -1 & \phantom{-}0 & \phantom{-}0\\
-1 & \phantom{-}3 & -1 & -1\\
\phantom{-}0 & -1 & \phantom{-}2 & -1\\
\phantom{-}0 & -1 & -1 & \phantom{-}2
\end{bmatrix}\]

Then you get $L = \begin{bmatrix} \phantom{-}1 & -1 & \phantom{-}0 & \phantom{-}0\\ -1 & \phantom{-}3 & -1 & -1\\ \phantom{-}0 & -1 & \phantom{-}2 & -1\\ \phantom{-}0 & -1 & -1 & \phantom{-}2 \end{bmatrix}$

Soroban · **Posted:** Thu, 9 Oct 2008 00:15:26 UTC

Hello, Starx!

I use \text{-} to produce a short minus-sign.

. . and it too is laborious . . .

Code:

[tex] L = \begin{bmatrix}
1 & \text{-}1 & 0 & 0 \\
\text{-}1 & 3 & \text{-}1 & \text{-}1 \\
0 & \text{-}1 & 2 & \text{-}1 \\
0 & \text{-}1 & \text{-}1 & 2
\end{bmatrix} [/tex] 

$L = \begin{bmatrix} 1 & \text{-}1 & 0 & 0\\ \text{-}1 & 3 & \text{-}1 & \text{-}1\\ 0 & \text{-}1 & 2 & \text{-}1\\ 0 & \text{-}1 & \text{-}1 & 2 \end{bmatrix}$

Opalg, I like that "phantom" feature!
Makes me want to experiment with it . . .

S.O.S. Mathematics CyberBoard

Formatting within a matrix...

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