To save math equation into database, a text format is more applicable. You can convert it to any format.
Refer to this question understanding a mathematica equation on mathematica.stackexchange.com, there are many math formula with many specified chars and in text format.
There are many ways to render a text formula.
<script type="math/tex" id="MathJax-Element-19">n(r) = frac{2pi r^2}{sqrt{3}}</script>
, the math equation is with text format n(r) = frac{2pi r^2}{sqrt{3}}
in latex format.
<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>n</mi><mo stretchy="false">(</mo><mi>r</mi><mo stretchy="false">)</mo><mo>=</mo><mfrac><mrow><mn>2</mn><mi>π</mi><msup><mi>r</mi><mn>2</mn></msup></mrow><msqrt><mn>3</mn></msqrt></mfrac></math>
is in mathml format.
You also can use a render in your server or a client render to render the text formual to a image, like <img src="https://example.com/?e=n(r) = frac{2pi r^2}{sqrt{3}}">
So you can choose a common formula format, when use it you can render it directly or convert it to other format, or image.
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