$\LaTeX$ Tests

Here are some tests of $\LaTeX$ using MathJax.

$$\int_{-\infty}^{\infty} e^{-x^2} dx$$

Is written with two dollar signs: $$\int_{-\infty}^{\infty} e^{-x^2} dx$$

inline example: $\sum_{i = 0}^N 2i = y$

is made with a single dollar sign: $\sum_{i = 0}^N 2i = y$

One overbrace:

$${a}^{b} - \overbrace{c}^{d}$$

Like so: $${a}^{b} - \overbrace{c}^{d}$$

$$\underbrace{a}_{b} - \underbrace{c}_{d}$$

Like this: $$\underbrace{a}_{b} - \underbrace{c}_{d}$$

Testing defining new macros in Hugo/MathJax

$$ \RR \dd{x} $$

Some arrays and matrices:

$$ \begin{aligned} \mathrm{equation1} &= 16 \\ \mathrm{equation2} &= 26 + 13 \end{aligned} $$$$ \begin{bmatrix} a & b \\ c & d \end{bmatrix} $$

are written like this:

$$
\begin{aligned}
     \mathrm{equation1} &= 16 \\
     \mathrm{equation2} &= 26 + 13
\end{aligned}
$$

$$
\begin{bmatrix}
a & b \\
   c & d
   \end{bmatrix}
$$

Fancy Letters

$$ \begin{aligned} \mathcal{ABCDEFGHIJKLMNOPQRSTUVWXYZ} & & \mathrm{\\mathcal\{ABC...\}} \\ \end{aligned} $$

Some Famous Equations

Sturm-Liouville Operator

$$ \mathcal{L}[u] = \frac{d}{dx}\left[p(x)\frac{d}{dx}u\right] + q(x)\,u + \lambda w(x)\,u = 0 $$

The Sturm-Liouville problem has some cool provable properties. And any second order ordinary differential equation can be cast into S-L form. Some of those properties are:

  • infinite number of real, unique eigenvalues $\lambda_1, \lambda_2, \lambda_3, …$
  • Corresponding to each $\lambda_n$ is an eigenfunction $u_n$ with exactly $n - 1$ zeros in $[a, b]$
  • Eigenfunctions are orthogonal with weight $w$
  • Eigenfunctions form a complete basis for a Hilbert space $L^2$ of functions
$$ \langle y_n, y_m\rangle = \int_{a}^{b}y_n(x)y_m(x)w(x)\,\mathrm{d}x = \delta_{nm} $$

on some finite interval $[a, b]$ and where $\delta_{nm}$ is the Kronecker delta function.

  • $p, q, w$ and $p’$ are continuous on $[a, b]$
  • $p(x) > 0$ and $w(x) > 0$ for all $x \in [a,,b]$
$$ \left\{ \ \begin{aligned} \alpha_1 u(a) + \alpha_2 u'(a) &= 0 \\ \beta_1 u(b) + \beta_2 u'(b) &= 0 \\ \end{aligned} \right. $$