# The forum now supports math equations via MathJax

#1

Spurred by @imagejan, I installed the discourse-mathjax plugin, which makes it much nicer to write formulas.

Examples below. Enjoy.

\sum_{i=0}^n i^2 = \frac{(n^2+n)(2n+1)}{6}

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 $|q|<1$}

From MathJax-play-area:

This expression \sqrt{3x-1}+(1+x)^2 is an example of an inline equation.

### The Cauchy-Schwarz Inequality

\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)

### A Cross Product Formula

\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}

### The probability of getting (k) heads when flipping (n) coins is

P(E) = {n \choose k} p^k (1-p)^{ n-k}

### An Identity of Ramanujan

\frac{1}{\Bigl(\sqrt{\phi \sqrt{5}}-\phi\Bigr) e^{\frac25 \pi}} = 1+\frac{e^{-2\pi}} {1+\frac{e^{-4\pi}} {1+\frac{e^{-6\pi}} {1+\frac{e^{-8\pi}} {1+\ldots} } } }

### Maxwell’s Equations

\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}

#2

Looks great but how do you preview the formulae being typed?

#3

For now, use an external site’s live preview such as this one.

#4

Preview rendering should work now (at least for relatively simple expressions), after today’s upgrade (thanks @ctrueden!).

#5

looks great…by the way, do you think this plugin will work with wordpress??I created math tests page on my website but there you cannot include special symbols and I’m thinking on how this can be done…thanks

#6

@Stephanie_Riggs Did you have a look at the MathJax-LaTeX plugin for WordPress?

#7

\frac{q^2}{(1-q)}
Testing equation functionality.This text will be hidden