[Tex/LaTex] Argument of \text@ has an extra } \end{align*}

alignmath-mode

Good day,

I am using the following code:

\documentclass[]{report}
\usepackage{amsmath}
\usepackage{graphicx}
\usepackage{breqn}
\usepackage{hyperref}
\usepackage{amstext}
\hypersetup{linktocpage}
\usepackage{float}
\usepackage{array}
\usepackage{url} 
\usepackage{chngpage}
\usepackage{cleveref}
\usepackage[parfill]{parskip}
\usepackage[labelfont={bf},font=small, margin=0.5cm]{caption}

\begin{document}
\begin{align*}
\left \{ NJ^{-1}T_d \right \}_\text{worst case}=\begin{bmatrix} 
0.0016  \\  
\pm 0.0003 \\  
0.0016  
\end{bmatrix}
\end{align*}

\end{document}

I end up with the error:

*Argument of \text@ has an extra } \end{align*}*

Any ideas?

Best Answer

I'm not a fan of breqn. If you really want to use it (but I find it strange you use align* instead of the breqn environments), remember that it redefines many things. In particular, _ has a meaning rather different from the usual one and the redefinition has the consequence that some constructs that are legal without it become illegal.

Add braces around \text{worst case}:

\[
\{ NJ^{-1}T_d \}_{\text{worst case}}=
\begin{bmatrix} 
0.0016  \\  
\pm 0.0003 \\  
0.0016  
\end{bmatrix}
\]

I've removed \left and \right that serve no purpose here; also a one line align* doesn't make sense. But these adjustments have nothing to do with the problem.

Related Solutions

[Tex/LaTex] The argument of foo has an extra }.

As already suggested, you shouldn't reenvent the wheel ...

\documentclass{article}
\usepackage{mathtools}
\begin{document}

\begin{align*}
  \Aboxed{1 &= 2 }\\
  1 &\ne 2
\end{align*}

\end{document}

enter image description here

[Tex/LaTex] Argument of align has an extra ‘}’

The expression

 f(t) = ((x_t - x_{t-1})}

has one opening brace and two closing braces and that triggering the error message. The proper way to write the expression would be

f(t) = ((x_t - x_{t-1}) + (x_{t-1} - x_{t-2}))

or even better

f(t) = \bigl((x_t - x_{t-1}) + (x_{t-1} - x_{t-2})\bigr)

so the outer parentheses will be longer and this will increase readability.

On a side note, as egreg has mentioned, your code has also some other problems: the center environment is not necessary here and will add extra unwanted vertical space. For a single equation you should use equation instead of align. You shouldn't use two consecutive align environments; you can use a gather environment instead.

It's not clear why you want to split in that way a single formula; the breaking point that you've chosen and the numbering schema introduce ambiguity since the reader could get the impression that you are talking about two different expressions instead of two parts of a same formula. Perhaps you culd consider using \underbraces? Here are some options:

\documentclass{article}
\usepackage{amsmath}

\begin{document}

\begin{gather}
    \label{avggrad}
    f(t) = \big((x_t - x_{t-1}) + (x_{t-1} - x_{t-2})\big) \times \frac{1}{2} \\ 
    \label{avggradsum}
  \frac{ \sum_{i=0}^{n-1} (x_{t-i}-x_{t-(i+1)}) }{n}
\end{gather}

\begin{equation}
    \label{avggrad}
    f(t) = \big((x_t - x_{t-1}) + (x_{t-1} - x_{t-2})\big) \times \frac{1}{2} \frac{ \sum_{i=0}^{n-1} (x_{t-i}-x_{t-(i+1)}) }{n}
\end{equation}

\begin{equation}
    \label{avggrad}
    f(t) = \underbrace{\big((x_t - x_{t-1}) + (x_{t-1} - x_{t-2})\big)}_{\text{some explanation}} \times \frac{1}{2} \underbrace{\frac{ \sum_{i=0}^{n-1} (x_{t-i}-x_{t-(i+1)}) }{n}}_{\text{some description}}
\end{equation}

\end{document}

enter image description here

Best Answer

Related Solutions

[Tex/LaTex] The argument of foo has an extra }.

[Tex/LaTex] Argument of align has an extra ‘}’

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