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9. KaTeX (Math)

mrkdwn renders mathematical formulas with KaTeX — fast and fully local.

Enable

Turn on Settings → Editor → KaTeX / Math.

Syntax

Block example:

$$
\int_0^\infty e^{-x}\,dx = 1
$$

• In Visual mode, formulas render live.
• In Raw mode, you see the raw KaTeX syntax.

What is Supported? (Whitelist)

KaTeX supports a clearly defined set of commands — deliberately not the entire LaTeX language. This keeps rendering fast and safe. Supported includes:

• Fractions & roots: \frac{a}{b}, \sqrt{x}, \sqrt[3]{x}
• Exponents & subscripts: x^2, a_i, x_{i}^{2}
• Greek letters: \alpha, \beta, \pi, \Sigma
• Sums/integrals/limits: \sum, \int, \prod, \lim
• Operators & relations: \times, \cdot, \leq, \geq, \neq, \approx
• Arrows: \to, \rightarrow, \Rightarrow, \leftrightarrow
• Sets & logic: \in, \subset, \cup, \cap, \forall, \exists
• Matrices & environments: \begin{matrix}…\end{matrix}, pmatrix, bmatrix, cases, aligned
• Accents: \hat{x}, \bar{x}, \vec{x}, \dot{x}
• Fonts: \mathbb{R}, \mathcal{L}, \mathbf{x}, \text{…}
• Auto-sized delimiters: \left( … \right), \left[ … \right]

Security/whitelist: Unsupported or potentially unsafe LaTeX macros (e.g. arbitrary \def/\newcommand with custom code, file access, external packages) are not executed. KaTeX renders only its vetted command set; unknown commands show an error hint instead of doing something “unexpected”. This keeps rendering deterministic and free of network/system access.

Full command list: see the official KaTeX overview of supported functions (Supported Functions / Support Table).

Examples

Inline: The solution is $x = \frac{-b \pm \sqrt{b^2-4ac}}{2a}$.

Block:
$$
\begin{aligned}
f(x) &= (x+1)^2 \\
     &= x^2 + 2x + 1
\end{aligned}
$$

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