5

How do I left-align selective equation blocks, i.e. not centered ?

I know how to do it for ALL equation blocks in the document setting

\usepackage[fleqn]{amsmath}
\setlength{\mathindent}{0pt}

in the preamble, but I only want to do this for some equation blocks.

\documentclass[pdftex,12pt,a4paper,english,dutch,leqno]{article}
\usepackage[top=1cm,right=1cm,bottom=1cm,left=1.5cm,noheadfoot]{geometry}
\usepackage{babel}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage[dvipsnames,table]{xcolor}
\usepackage{color}
\definecolor{vanillegeel}{RGB}{255,240,216}
\usepackage{empheq}

\begin{document}

De raaklijn aan $(x_{0},f(x_{0}))$ wordt algemeen bepaald met :
\begin{empheq}[box={\fboxsep=3pt\colorbox{vanillegeel}}]{align*}
\textnormal{$\begin{cases}z=f(x)\text{ is continu in }x_{0}\text{.}\\
f'(x_{0})=0\text{ : }z=f(x_{0})\text{ is de horizontale raaklijn.}\\
\lim_{x\to x_{0}} f'(x)=\pm\infty\text{ : }x=x_{0}\text{ is de verticale raaklijn.}\\
f'(x_{0})\in\mathbb{R}_{0}\text{ : }z-f(x_{0})=f'(x_{0})\cdot(x-x_{0})\text{ is de raaklijn.\hspace{-12pt}}\end{cases}$}\end{empheq}

\end{document}
2
  • Place '&' at the beginning of each line inside the empheq environment and do not use the cases environment. This is the easiest way to get what you want.
    – Daniel F
    Jul 17, 2015 at 16:23
  • Special case of Align equation left - TeX - LaTeX Stack Exchange. ■ nccmath 's environment can also be used, and would also works in general case.
    – user202729
    Apr 19 at 22:31

1 Answer 1

5

Don't use align*.

De raaklijn aan $(x_{0},f(x_{0}))$ wordt algemeen bepaald met:
\begin{flushleft}
\colorbox{vanillegeel}{%
$\displaystyle
\begin{cases}
z=f(x) \text{ is continu in } x_{0}.
\\
f'(x_{0})=0 \text{ : } z=f(x_{0}) \text{ is de horizontale raaklijn.}
\\
\lim_{x\to x_{0}} f'(x)=\pm\infty \text{ : } x=x_{0} \text{ is de verticale raaklijn.}
\\
f'(x_{0})\in\mathbb{R}_{0} \text{ : } z-f(x_{0})=f'(x_{0})\cdot(x-x_{0})
  \text{ is de raaklijn.}
\end{cases}
$\kern-\nulldelimiterspace\kern-2\arraycolsep}
\end{flushleft}

enter image description here

6
  • What does \kern-\nulldelimiterspace\kern-2\arraycolsep} do in this ?
    – Petoetje59
    Oct 5, 2012 at 14:28
  • @Petoetje59 It's a substitute of your \hspace{-12pt} based on document parameters, rather than "calculation by eye".
    – egreg
    Oct 5, 2012 at 14:45
  • Not allowing you to get the unsung hero badge! ;) +1.
    – user11232
    Oct 5, 2012 at 14:48
  • @HarishKumar Darn!
    – egreg
    Oct 5, 2012 at 14:49
  • How come \begin{align*} doesn't work but flushleft does?
    – Fraïssé
    Sep 1, 2015 at 8:18

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