# Latex multicolumn problem

1. Jun 2, 2012

### lavster

Can anyone tell me what is wrong with what ive written here - its coming up with lots of errors (inlcuded below). I have the \usepackage{multirow} at the beginning. Thanks

[tex]
\begin{table}[h]
\caption{Investigation of interleaf leakage using ion chamber}
\begin{center}
\begin{tabular}{c c c c}

\hline\hline
MLC open/closed & Position from Original (mm) & Reading (per 200MU) & $\mbox{~~}$ Average $\mbox{~~}$ \\ [0.5ex]
\hline\hline
open & 0 & 4.27, 4.26 & $\mbox{~~}$ 4.265 \\
closed & 0 & 0.49 &
\begin{flushleft}
$$\mbox{~~}$$\ldelim \} {3} {7mm} \multirow{3}{*}{0.0493}
\end{flushleft}
\\

closed & 1 & 0.50 & \\
closed & 2 & 0.49 & \\ [1ex]
\hline
\end{tabular}
\label{rubbish}
\end{center}
\caption{Uncertainty of the Measurement}
\begin{center}
\begin{tabular}{c c}

\hline\hline
Source of uncertainty & Uncertainty \\ [0.5ex]
\hline\hline
standard deviation & see equation \ref{SD} \\
scale reading & $\pm$0.01mm \\
response of electrometer & $\pm$0.5\% \\
reproducibility of unit & $\pm$1\% \\

\hline
& \\
where, & \\
\multicolumn{2}{c}{

\mbox{~~~~~~~~~~~~~~~~~~~~~~~~~~~}StandardDeviation = \sqrt{\frac{\sum^{n}_{i=0}(x_i-\bar{x})}{n-1}},\mbox{~~~~~~~~~~~~~~~~~~~~~~~~~~~}
\label{SD}

} \\
& \\
\multicolumn{2}{c}{where $\bar{x}$ is the average value, $x_i$ is the i-th reading and $n$ is the total number of readings.} \\
\end{tabular}
\label{uncert}
\end{center}
\end{table}

[\tex]

! LaTeX Error: Something's wrong--perhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...

l.649 \begin{flushleft}

Try typing <return> to proceed.
If that doesn't work, type X <return> to quit.

! LaTeX Error: Something's wrong--perhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...

l.649 \begin{flushleft}

Try typing <return> to proceed.
If that doesn't work, type X <return> to quit.

! LaTeX Error: Something's wrong--perhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...

l.649 \begin{flushleft}

Try typing <return> to proceed.
If that doesn't work, type X <return> to quit.

! LaTeX Error: Something's wrong--perhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...

l.651 \end{flushleft}

Try typing <return> to proceed.
If that doesn't work, type X <return> to quit.

! LaTeX Error: Something's wrong--perhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...

l.651 \end{flushleft}

Try typing <return> to proceed.
If that doesn't work, type X <return> to quit.

! LaTeX Error: Something's wrong--perhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...

l.651 \end{flushleft}

Try typing <return> to proceed.
If that doesn't work, type X <return> to quit.

! Missing $inserted. <inserted text>$
l.680 }
\\
I've inserted a begin-math/end-math symbol since I think
you left one out. Proceed, with fingers crossed.

! You can't use \eqno' in math mode.
\endmathdisplay@a ...\df@tag \@empty \else \veqno
\alt@tag \df@tag \fi \ifx ...
l.680 }
\\
Sorry, but I'm not programmed to handle this case;
I'll just pretend that you didn't ask for it.
If you're in the wrong mode, you might be able to
return to the right one by typing I}' or I$' or I\par'. ! Missing$ inserted.
<inserted text>
\$
l.680 }
\\
I've inserted something that you may have forgotten.
(See the <inserted text> above.)
With luck, this will get me unwedged. But if you
really didn't forget anything, try typing `2' now; then
my insertion and my current dilemma will both disappear.

2. Jun 2, 2012

### lavster

also how to I insert my text properly?!

3. Jun 24, 2012

### Stefan_K

For properly inserting code, use the "Code" button in the post editor.

Regarding the problem: you cannot use a flushleft environment within tabular cells. It's implemented as a list environment, that's why you got the error "Missing \item" because a list consists of items. You could use \raggedright instead.

Also, you cannot use an equation environment within a normal tabular cell. It would work in a paragraph cell, made with the p column specifier, or within \parbox or a minipage environment.

Further tipps:

• Use more table placement options, such as [!htbp] instead of just [h], to allow more flexible placement. You can find an explanation of these options on LaTeX-Community.org in the post Order of appearance of tables and figures
• I would not use a center environment within in a table environment, this adds additional vertical space. Instead, I would use \centering. See center vs. \centering for an explanation.
• \mbox{~~~~~~~~~~~~~~~~~~~~~~~~~~~} and similar are strange fixes - you could use \hspace but better would be a proper automatic alignment.
• Several labels in a table environment could be a problem - perhaps use the subcaption or the subfig package.
• I strongly recommend to use the booktabs package for nice table design.

Stefan