Alignment of Matrix Equations

Question

I want the code below to appear in one line but the last array (the transposed one) appears on the line below. What should I do?

\begin{equation}

 X'X=(V_r,V_{p-r}) \[ \left( \begin{array}{cc}
 \Lambda_r & 0 \\
 0 & \Lambda_{p-r} \end{array} \right)\] \[ \left( \begin{array}{c}
 V'_r\\
 V'_{p-r} \end{array} \right)\]

 \end{equation}

score 2 · Accepted Answer · edited Apr 13 '17 at 12:36

2

\[...\] initiates a display math environment, which you don't need inside the equation environment, since you're already inside math mode.

enter image description here

\documentclass{article}
\begin{document}
\begin{equation}
  X'X = (V_r, V_{p-r}) \left( \begin{array}{cc}
    \Lambda_r & 0 \\
    0 & \Lambda_{p-r}
  \end{array} \right) \left( \begin{array}{c}
    V'_r \\
    V'_{p-r}
  \end{array} \right)
\end{equation}
\end{document}

Also see Where is the \matrix command? for more ways of typesetting matrices.

Here is a minor adjustment that uses the \biggl/\biggr pair rather than \left/\right, and also reduces the outer column specification:

enter image description here

\documentclass{article}
\begin{document}
\begin{equation}
  X'X = (V_r, V_{p-r}) \biggl( \begin{array}{@{}cc@{}}
    \Lambda_r & 0 \\
    0 & \Lambda_{p-r}
  \end{array} \biggr) \biggl( \begin{array}{@{}c@{}}
    V'_r \\
    V'_{p-r}
  \end{array} \biggr)
\end{equation}
\end{document}

edited Apr 13 '17 at 12:36

Community

1

answered Jan 31 '14 at 21:20

Werner

603,163

2

One might as well replace the \biggl(\begin{array}{@{}cc@{}}...\end{array}\biggr) with \begin{pmatrix}...\end'pmatrix} from amsmath so as to have something lighter to type, I think. – Bernard Jan 31 '14 at 21:29
@Bernard: ...hence the reference to Where is the \matrix command? – Werner Jan 31 '14 at 21:30
Oops! I apologise not to have seen all the details – just wondered why you hadn't proposed this environment. – Bernard Jan 31 '14 at 22:25

Alignment of Matrix Equations

1 Answers1