Text Formatting ⇒ Matrix Alignment Error

[knip]

I didn't understand why the following code works.

Code: Select all

\begin{tabular}{l|lllllllllll|}
& (j-1)(k-j) & (j-1)(k-j-1) & (j-1)(k-j-2) & \dots & j-1 & 0 & - & - & - & \dots & - \\
& (j-2)(k-j+1) & (j-2)(k-j) & (j-1)(k-j-1) & \dots & \dots & j-2 & 0 & - & - & \dots & - \\
& \vdots & \vdots & \vdots & \dots & \dots & \dots & \dots & 0 & - & \dots & - \\
H = &2(k-3) & 2(k-4) & 2(k-5) & \dots & \dots & \dots & \dots & 2 & 0 & - & - \\
&(k-2) & (k-3) & (k-4) & \dots & \dots & \dots & \dots & \dots & 1 & 0 & - \\
&0 & 0 & 0 & \dots & \dots & \dots & \dots & \dots & \dots & \dots & 0 \\
\end{tabular}

And otherwise using the matrix environment I got this error

Extra alignment tab has been changed to \cr.

Code: Select all

$$
H = 
\begin{bmatrix}
(j-1)(k-j) & (j-1)(k-j-1) & (j-1)(k-j-2) & \dots & j-1 & 0 & - & - & - & \dots & - \\
(j-2)(k-j+1) & (j-2)(k-j) & (j-1)(k-j-1) & \dots & \dots & j-2 & 0 & - & - & \dots & - \\
\vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots & 0 & - & \dots & - \\
2(k-3) & 2(k-4) & 2(k-5) & \dots & \dots & \dots & \dots & 2 & 0 & - & - \\
(k-2) & (k-3) & (k-4) & \dots & \dots & \dots & \dots & \dots & 1 & 0 & - \\
0 & 0 & 0 & \dots & \dots & \dots & \dots & \dots & \dots & \dots & 0 \\
\end{bmatrix}
$$

thank you guys for your help

[localghost]

Please always prepare a self-contained and minimal example to give an adequate problem description. Otherwise it is nearly impossible to comprehend a problem and a thread may be left orphaned. People are rarely motivated to build such an example just for testing possible solutions.

The matrix environment that comes from amsmath uses internally the MaxMatrixCols counter. This counter is set to 10 by default. You have to increase it correspondingly.

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\documentclass[11pt]{article}
\usepackage[T1]{fontenc}
\usepackage{geometry}
\usepackage{mathtools}  % loads »amamsth«

\setcounter{MaxMatrixCols}{11}  % <<< This is your set screw

\begin{document}
  \[
    H =
    \begin{bmatrix}
      (j-1)(k-j) & (j-1)(k-j-1) & (j-1)(k-j-2) & \dots & j-1 & 0 & - & - & - & \dots & - \\
      (j-2)(k-j+1) & (j-2)(k-j) & (j-1)(k-j-1) & \dots & \dots & j-2 & 0 & - & - & \dots & - \\
      \vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots & 0 & - & \dots & - \\
      2(k-3) & 2(k-4) & 2(k-5) & \dots & \dots & \dots & \dots & 2 & 0 & - & - \\
      (k-2) & (k-3) & (k-4) & \dots & \dots & \dots & \dots & \dots & 1 & 0 & - \\
      0 & 0 & 0 & \dots & \dots & \dots & \dots & \dots & \dots & \dots & 0 \\
    \end{bmatrix}
  \]
\end{document}

Unfortunately this is described only in a footnote in Section 4.1 of the amsmath manual.

Remarks:

• Do not use $$ … $$ to create unnumbered displayed equations. It causes several effects that are mostly not wanted. The correct LaTeX syntax is \[ … \] (see above code).

Further reading:

• The »Math mode« document.

Best regards and welcome to the board
Thorsten