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Mathematics · Astro Book

Mathematics

Inline notation

A short expression belongs inside its sentence: for a real number x∈Rx \in \RR, the quantity x2x^2 is nonnegative. Inline math uses single dollar delimiters.

For $x \in \RR$, the quantity $x^2$ is nonnegative.

This site defines \RR as a macro for \mathbb{R}. The formula is rendered into HTML and MathML during the build.

Display equations

The quadratic formula is a useful display example:

x=−b±b2−4ac2a,a≠0.x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}, \qquad a \ne 0.

Use a pair of double dollar delimiters for display math:

$$
x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}
$$

Matrices and aligned expressions

A=(1234),det⁡(A)=1⋅4−2⋅3=−2.A = \begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix}, \qquad \det(A) = 1\cdot4 - 2\cdot3 = -2. ∫01x2 dx=[x33]01=13.\begin{aligned} \int_0^1 x^2\,dx &= \left[\frac{x^3}{3}\right]_0^1 \\ &= \frac{1}{3}. \end{aligned}

Long expressions

Wide formulas stay in their own scrolling region on small screens:

f(x1,x2,x3,x4,x5,x6,x7,x8)=∑i=18xi2+∏i=18(1+xi)+∂2f∂x1∂x2+∂2f∂x3∂x4f(x_1,x_2,x_3,x_4,x_5,x_6,x_7,x_8)=\sum_{i=1}^{8}x_i^2+\prod_{i=1}^{8}(1+x_i)+\frac{\partial^2 f}{\partial x_1\partial x_2}+\frac{\partial^2 f}{\partial x_3\partial x_4}

Macros and validation

astro.config.mjs

astroBook({
  markdown: {
    math: {
      macros: { '\\RR': '\\mathbb{R}' },
      throwOnError: false,
    },
  },
});

The default keeps invalid math readable. This deliberately unknown command demonstrates that fallback: \unknowncommandx\unknowncommand{x}.

Use throwOnError: true when an invalid expression should fail the build. The theme uses KaTeX math syntax; it does not compile complete LaTeX documents.