KaTeX and MathJax Comparison Demo, currently processed as KaTex

Repeating fractions

1(ϕ5ϕ)e25π1+e2π1+e4π1+e6π1+e8π1+ \frac{1}{\Bigl(\sqrt{\phi \sqrt{5}}-\phi\Bigr) e^{\frac25 \pi}} \equiv 1+\frac{e^{-2\pi}} {1+\frac{e^{-4\pi}} {1+\frac{e^{-6\pi}} {1+\frac{e^{-8\pi}} {1+\cdots} } } }

Summation notation

(k=1nakbk)2(k=1nak2)(k=1nbk2) \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)

Sum of a Series

I broke up the next two examples into separate lines so it behaves better on a mobile phone. That’s why they include \displaystyle.

i=1k+1i \displaystyle\sum_{i=1}^{k+1}i

=(i=1ki)+(k+1) \displaystyle= \left(\sum_{i=1}^{k}i\right) +(k+1)

=k(k+1)2+k+1 \displaystyle= \frac{k(k+1)}{2}+k+1

=k(k+1)+2(k+1)2 \displaystyle= \frac{k(k+1)+2(k+1)}{2}

=(k+1)(k+2)2 \displaystyle= \frac{(k+1)(k+2)}{2}

=(k+1)((k+1)+1)2 \displaystyle= \frac{(k+1)((k+1)+1)}{2}

Product notation

1+q2(1q)+q6(1q)(1q2)+=j=01(1q5j+2)(1q5j+3), for q<1. \displaystyle 1 + \frac{q^2}{(1-q)}+\frac{q^6}{(1-q)(1-q^2)}+\cdots = \displaystyle \prod_{j=0}^{\infty}\frac{1}{(1-q^{5j+2})(1-q^{5j+3})}, \displaystyle\text{ for }\lvert q\rvert < 1.

Inline math

And here is some in-line math: kn+1=n2+kn2kn1 k_{n+1} = n^2 + k_n^2 - k_{n-1} , followed by some more text.

Greek Letters

Γ Δ Θ Λ Ξ Π Σ Υ Φ Ψ Ωα β γ δ ϵ ζ η θ ι κ λ μ ν ξ ο π ρ σ τ υ ϕ χ ψ ω ε ϑ ϖ ϱ ς φ \Gamma\ \Delta\ \Theta\ \Lambda\ \Xi\ \Pi\ \Sigma\ \Upsilon\ \Phi\ \Psi\ \Omega \alpha\ \beta\ \gamma\ \delta\ \epsilon\ \zeta\ \eta\ \theta\ \iota\ \kappa\ \lambda\ \mu\ \nu\ \xi \ \omicron\ \pi\ \rho\ \sigma\ \tau\ \upsilon\ \phi\ \chi\ \psi\ \omega\ \varepsilon\ \vartheta\ \varpi\ \varrho\ \varsigma\ \varphi

Arrows

          \gets\ \to\ \leftarrow\ \rightarrow\ \uparrow\ \Uparrow\ \downarrow\ \Downarrow\ \updownarrow\ \Updownarrow

           \Leftarrow\ \Rightarrow\ \leftrightarrow\ \Leftrightarrow\ \mapsto\ \hookleftarrow \leftharpoonup\ \leftharpoondown\ \rightleftharpoons\ \longleftarrow\ \Longleftarrow\ \longrightarrow

      \Longrightarrow\ \longleftrightarrow\ \Longleftrightarrow\ \longmapsto\ \hookrightarrow\ \rightharpoonup

      \rightharpoondown\ \leadsto\ \nearrow\ \searrow\ \swarrow\ \nwarrow

Symbols

          \surd\ \barwedge\ \veebar\ \odot\ \oplus\ \otimes\ \oslash\ \circledcirc\ \boxdot\ \bigtriangleup

          \bigtriangledown\ \dagger\ \diamond\ \star\ \triangleleft\ \triangleright\ \angle\ \infty\ \prime\ \triangle

Calculus

udvdx,dx=uvdudxv,dx \int u \frac{dv}{dx},dx=uv-\int \frac{du}{dx}v,dx

f(x)=f^(ξ),e2πiξx f(x) = \int_{-\infty}^\infty \hat f(\xi),e^{2 \pi i \xi x}

Fds=0 \oint \vec{F} \cdot d\vec{s}=0

Lorenz Equations

x˙=σ(yx) y˙=ρxyxz z˙=βz+xy \begin{aligned} \dot{x} & = \sigma(y-x) \ \dot{y} & = \rho x - y - xz \ \dot{z} & = -\beta z + xy \end{aligned}

Cross Product

This works in KaTeX, but the separation of fractions in this environment is not so good.

V1×V2=ijk XuYu0 XvYv0 \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}

Here’s a workaround: make the fractions smaller with an extra class that targets the spans with “mfrac” class (makes no difference in the MathJax case):

V1×V2=ijk XuYu0 XvYv0 \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}

Accents

x^ x x¨ \hat{x}\ \vec{x}\ \ddot{x}

Stretchy brackets

(x2y3) \left(\frac{x^2}{y^3}\right)

Evaluation at limits

x3301 \left.\frac{x^3}{3}\right|_0^1

Case definitions

f(n)={n2,if n is even 3n+1,if n is odd f(n) = \begin{cases} \frac{n}{2}, & \text{if } n\text{ is even} \ 3n+1, & \text{if } n\text{ is odd} \end{cases}

Maxwell’s Equations

×B,1c,Et=4πcj E=4πρ ×E,+,1c,Bt=0 B=0 \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}

These equations are quite cramped. We can add vertical spacing using (for example) [1em] after each line break (\). as you can see here:

$$ \begin{aligned} \nabla \times \vec{\mathbf{B}} -, \frac1c, \frac{\partial\vec{\mathbf{E}}}{\partial t} & = \frac{4\pi}{c}\vec{\mathbf{j}} \[1em] \nabla \cdot \vec{\mathbf{E}} & = 4 \pi \rho \[0.5em] \nabla \times \vec{\mathbf{E}}, +, \frac1c, \frac{\partial\vec{\mathbf{B}}}{\partial t} & = \vec{\mathbf{0}} \[1em] \nabla \cdot \vec{\mathbf{B}} & = 0 \end{aligned} $$

Statistics

Definition of combination:

n!k!(nk)!=nCk(nk) \frac{n!}{k!(n-k)!} = {^n}C_k {n \choose k}

Fractions on fractions

1x+1yyz \frac{\frac{1}{x}+\frac{1}{y}}{y-z}

n-th root

1+x+x2+x3+n \sqrt[n]{1+x+x^2+x^3+\ldots}

Matrices

(a11a12a13 a21a22a23 a31a32a33)[00  00] \begin{pmatrix} a_{11} & a_{12} & a_{13}\ a_{21} & a_{22} & a_{23}\ a_{31} & a_{32} & a_{33} \end{pmatrix} \begin{bmatrix} 0 & \cdots & 0 \ \vdots & \ddots & \vdots \ 0 & \cdots & 0 \end{bmatrix}

Punctuation

f(x)=1+x(x1)f(x)x2(x) f(x) = \sqrt{1+x} \quad (x \ge -1) f(x) \sim x^2 \quad (x\to\infty)

Now with punctuation:

f(x)=1+x,x1f(x)x2,x f(x) = \sqrt{1+x}, \quad x \ge -1 f(x) \sim x^2, \quad x\to\infty