Mathjax v3

Setup

You'll need to add the following lines in your layout (and discard KaTeX ones if there are any to avoid clashes):

<script>
MathJax = {
  tex: {
    inlineMath: [['\\(', '\\)']],
    tags: 'all'
  },
  svg: {fontCache: 'global'}
};
</script>
<script id="MathJax-script" async src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-svg.js"></script>

Todo

fix references
environments with * should be ignored by Franklin and left to MathJax
...

Demos

When $a \neq 0$, there are two solutions to $ax^2+bx+c=0$ and they are

\[ x = {-b \pm \sqrt{b^2-4ac} \over 2a} \]

The Lorenz Equations

\[\begin{aligned} \dot{x} &= \sigma(y-x) \\ \dot{y} &= \rho x - y - xz \\ \dot{z} &= -\beta z + xy \end{aligned}\]

Cauchy Schwarz

\[ \left( \sum_{k=1}^n a_k b_k \right)^{\!\!2} \leq \left( \sum_{k=1}^n a_k^2 \right) \left( \sum_{k=1}^n b_k^2 \right) \]

\[ \mathbf{V}_1 \times \mathbf{V}_2 = \begin{vmatrix} \mathbf{i} & \mathbf{j} & \mathbf{k} \\ \frac{\partial X}{\partial u} & \frac{\partial Y}{\partial u} & 0 \\ \frac{\partial X}{\partial v} & \frac{\partial Y}{\partial v} & 0 \\ \end{vmatrix} \]

Rogers-Ramanujan

\[ 1 + \frac{q^2}{(1-q)}+\frac{q^6}{(1-q)(1-q^2)}+\cdots = \prod_{j=0}^{\infty}\frac{1}{(1-q^{5j+2})(1-q^{5j+3})}, \quad\quad \text{for $|q| < 1$}. \]

Maxwell

\[\begin{aligned} \nabla \times \vec{\mathbf{B}} -\, \frac1c\, \frac{\partial\vec{\mathbf{E}}}{\partial t} &= \frac{4\pi}{c}\vec{\mathbf{j}} \\ \nabla \cdot \vec{\mathbf{E}} &= 4 \pi \rho \\ \nabla \times \vec{\mathbf{E}}\, +\, \frac1c\, \frac{\partial\vec{\mathbf{B}}}{\partial t} &= \vec{\mathbf{0}} \\ \nabla \cdot \vec{\mathbf{B}} &= 0 \end{aligned}\]

More inline

Finally, while display equations look good for a page of samples, the ability to mix math and text in a paragraph is also important. This expression $\sqrt{3x-1}+(1+x)^2$ is an example of an inline equation. As you see, MathJax equations can be used this way as well, without unduly disturbing the spacing between lines.

Testing links

Here's one using the equation environment:

\[\begin{equation} x+1\over\sqrt{1-x^2} \end{equation}\]

and one with equation* environment:

\[\begin{equation*} x+1\over\sqrt{1-x^2} \end{equation*}\]

This is a forward reference (9) for the following equation:

\[x+1\over\sqrt{1-x^2}\]

More math:

\[x+1\over\sqrt{1-x^2}\]