# Content

The content of a chapter of a book can be a standard Markdown file (`.md`

) or a `.nim`

file.

The nim file must be a nimib document and the default content (created by `init`

command) is:

```
import nimib, nimibook
nbInit(theme = useNimibook)
nbText: "## Default Content"
nbSave
```

## Latex

Latex is available through Katex as in Nimib. It is enabled on a specific document with the command

`nb.useLatex`

which adds the following content in the head of the document:

```
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.12.0/dist/katex.min.css" integrity="sha384-AfEj0r4/OFrOo5t7NnNe46zW/tFgW6x/bCJG8FqQCEo3+Aro6EYUG4+cU+KJWu/X" crossorigin="anonymous">
<script defer src="https://cdn.jsdelivr.net/npm/katex@0.12.0/dist/katex.min.js" integrity="sha384-g7c+Jr9ZivxKLnZTDUhnkOnsh30B4H0rpLUpJ4jAIKs4fnJI+sEnkvrMWph2EDg4" crossorigin="anonymous"></script>
<script defer src="https://cdn.jsdelivr.net/npm/katex@0.12.0/dist/contrib/auto-render.min.js" integrity="sha384-mll67QQFJfxn0IYznZYonOWZ644AWYC+Pt2cHqMaRhXVrursRwvLnLaebdGIlYNa" crossorigin="anonymous" onload="renderMathInElement(document.body,{delimiters:[{left: '$$', right: '$$', display: true},{left: '$', right: '$', display: false}]});"></script>
```

## Inline equations

**Inline equations** are obtained with delimiters `$ ... $`

. The following inline paragraph:

Euler's identity is the equality $e^{i\pi} + 1 = 0$, where $e$ is the base of natural logarithms, $i$ is the imaginary unit, and $\pi$ is the ratio of circumference of a circle to its diameter.

...is created with the following source:

```
> Euler's identity is the equality
> $e^{i\pi} + 1 = 0$, where $e$ is the base of natural logarithms,
> $i$ is the imaginary unit, and $\pi$ is the ratio of circumference of a circle
> to its diameter.
```

## Block equations

**Block equations** are obtained with delimiters `$$ ... $$`

. The follwing block equation:

$$ f(x) = \frac{1}{\sigma\sqrt{2\pi}} \exp\left( -\frac{1}{2}\left(\frac{x-\mu}{\sigma}\right)^{!2},\right) $$

...is created with the following source:

```
$$
f(x) = \frac{1}{\sigma\sqrt{2\pi}}
\exp\left( -\frac{1}{2}\left(\frac{x-\mu}{\sigma}\right)^{\!2}\,\right)
$$
```

### MathJax support

As in the original mdbook, you can opt instead to activate MathJax support with:

```
nb.context["mathjax_support"] = true
```