The majority of this post was written by bobble and Deusovi.
TL;DR: Use plain text instead of MathJax when possible.
When should I use MathJax instead of plain text?
Many people browse the Internet using screen readers, most of which struggle to process MathJax. Only a few expensive ones can handle MathJax directly. Others require a wonky extension which doesn't work sometimes. Some just can’t read it at all.. If you write "$1$" instead of "1", there will be people who are unable to read your post as intended.
It’s not just screen readers that have trouble: people with dyslexia can find the fancy cursive script that MathJax uses difficult to read. Switching back and forth between regular text and fancy MathJax variables, for instance, will significantly harm readability.
So, the solution is simple: Only use MathJax when you need its equation formatting. If you could write the same thing in plain text, then use plain text instead.
Lots of math can be represented just fine without MathJax:
MathJax input | MathJax | Unicode / plain text | Markdown input | Markdown | |
---|---|---|---|---|---|
Numbers | $729,\sqrt{2}, 180^\circ$ |
$729, \sqrt{2}, 180^\circ$ | 729, √2, 180° | ||
Variables | $a$ |
$a$ | 𝑎 | _a_ |
a |
Arithmetic | $+, -, \div, \times$ |
$+,-,\div,\times$ | +,-,÷,× | ||
Inequalities | $>, <, \geq, \leq$ |
$>,<,\geq,\leq$ | >, <, ≥, ≤ | ||
Superscripts and Subscripts | $a^b, a_b$ |
$a^b, a_b$ | a<sup>b</sup>, a<sub>b</sub> |
ab, ab | |
Greek | $\pi, \theta, \epsilon$ |
$\pi, \theta, \epsilon$ | π, θ, ε |
It's true that sometimes, math really is too complicated to write up without MathJax. This is what MathJax was designed for! But you should only use it when it actually improves an equation's readability. If you don't need any fancy math formatting features of MathJax in particular, then use plain text.
MathJax also takes a considerable amount of time to load. The more MathJax on the page, the longer this takes. Also don't use MathJax for $fancy\ italic\ fonts$ either; it renders terribly and, simply put, is not math. There's already *markdown* for italics, and sans-serif fonts are easier to read.
$\sqrt{2}$
is rendered as the unicode character for the square root followed by a 2, just with another font. There are also many<span>
s for positioning, but if the screen reader just ignores them the read part is exactly the same as if it was Markdown. $\endgroup$