How to change alignment of displayed equations in IPython Notebook? - jupyter-notebook

Question

I would like my MathJax displayed equations in IPython Notebook to be aligned at the left instead of centered. This is controlled by a core configuration option displayAlign in MathJax as described here.
I have tried to set this option in IPython Notebook by adding this to my config.js file
MathJax.Hub.Config({
displayAlign: "left"
});
but it doesn't have any effect.
How can I set MathJax core configuration options in IPython Notebook?
[Update] I have found one way that works: add the above configuration lines not to config.js but to mathjaxutils.js. In my case (Windows 8) this file is found here: C:\Anaconda\Lib\site-packages\IPython\html\static\notebook\js\mathjaxutils‌​.js. This is not a great solution though because it involves modifying a file that will presumably get overwritten the next time I update IPython.
[Update] The technique suggested by #Ian in the comments does work, but just one notebook at a time. To summarize, I created a file my_css.css whose content is
<script>
MathJax.Hub.Config({
displayAlign: 'left'
});
</script>
In the notebook, if I run this cell
from IPython.core.display import HTML
css_file = 'my_css.css'
HTML(open(css_file, "r").read())
displayed equations do get left aligned, as desired.
However, I would like this to be the default for all my notebooks. I tried adding this to my custom.js
MathJax.Hub.Config({
displayAlign: 'left'
});
and for good measure added this to my custom.css
<script>
MathJax.Hub.Config({
displayAlign: 'left'
});
</script>
But neither has any effect. If there is a way to make this setting a default for all notebooks without modifying the core IPython files, that would be perfect.

Answer 1

Use \begin{align} and \end{align}. This does not exactly answer the question but it has the desired effect. For example try:
$
\begin{align}
\frac{1}{2} \times \frac{3}{2} = \frac{3}{4}
\end{align}
$
The above renders exactly the same as,
$$
\frac{1}{2} \times \frac{3}{2} = \frac{3}{4}
$$
except that it is left justified.
This approach has the added advantage that other alignments can be be added, as in:
$
\begin{align}
\dot{x} & = \sigma(y-x) \\
\dot{y} & = \rho x - y - xz \\
\dot{z} & = -\beta z + xy
\end{align}
$
This last code block is from Motivating Examples in the Jupyter Notebook docs.
Other examples of aligning equations can be found here Aligning several equations

Answer 2

In Jupyter lab, I find that using a single $ left aligns, whereas double $ centers the equations
$
\begin{align}
c & = (0,\mu)+(a,b)\\
& =(a, b+\mu)
\end{align}
$
is left aligned whereas
$$
\begin{align}
c & = (0,\mu)+(a,b)\\
& =(a, b+\mu)
\end{align}
$$
is centered

Answer 3

You could try including a css file. For example, this set of notebooks pulls in this css file (see the final cell in the notebook) which does explicitly set the displayAlign tag, although it sets it to center.