# [Tex/LaTex] Labeling equations and math mode

equationslabelsmath-mode

I have to write the equation shown below in Latex and I am using

{\textbf{q}=($\mu$  $_1$ $\mu$  $_2$ ... $\mu$  $_{n-2}$
$\mu$ $_n$ )\textsuperscript{T}}


and it comes OK.

However, I need to label the equation and I am using

$${\textbf{q}=(\mu _1 \mu _2 ... \mu _{n-2} \mu _n )\textsuperscript{T}} \label{2}$$


but I am getting errors stating that there is a missing } and that math mode should end with .

Also how can the equation below be written using Latex:

Example, how this can be typeset:

\documentclass[a5paper]{article}
\usepackage{amsmath}

\newcommand*{\transpose}{\mathrm{T}}
\newcommand*{\vc}[1]{\mathhbf{#1}}
% \vec and \vector are already defined

\begin{document}
$$\label{q-def} \vc{q} = (\mu_1, \mu_2, \dots, \mu_{n-1}, \mu_{n})^\transpose$$
Equation~\eqref{q-def} defines vector $\vc{q}$.
\end{document}


Or as matrix without commas:

\documentclass[a5paper]{article}
\usepackage{amsmath}

\newcommand*{\transpose}{\mathrm{T}}
\newcommand*{\vc}[1]{\mathbf{#1}}

\begin{document}
$$\label{q-def} \vc{q} = \begin{pmatrix} \mu_1 & \mu_2 & \dots & \mu_{n-1} & \mu_{n} \end{pmatrix}^\transpose$$
Equation~\eqref{q-def} defines vector $\vc{q}$.
\end{document}


## Second question

The equation can be typeset as:

\documentclass{article}
\usepackage{amsmath}

\begin{document}
$L = \log(l) = \sum_{i=1}^{N} \bigl( \log ( \mathbf{s}(\exp \{ \mathbf{Q} t_i\}) \mathbf{q} ) \bigr)$
\end{document}