# 6 Blocks

## 6.1 Equations

Here is an equation.

\[\begin{equation} f\left(k\right) = \binom{n}{k} p^k\left(1-p\right)^{n-k} \tag{6.1} \end{equation}\]

You may refer to using `\@ref(eq:binom)`

, like see Equation (6.1).

## 6.2 Theorems and proofs

Labeled theorems can be referenced in text using `\@ref(thm:tri)`

, for example, check out this smart theorem 6.1.

**Theorem 6.1 **For a right triangle, if \(c\) denotes the *length* of the hypotenuse
and \(a\) and \(b\) denote the lengths of the **other** two sides, we have
\[a^2 + b^2 = c^2\]

Read more here https://bookdown.org/yihui/bookdown/markdown-extensions-by-bookdown.html.

## 6.3 Callout blocks

The `bs4_book`

theme also includes special callout blocks, like this `.rmdnote`

.

You can use **markdown** inside a block.

```
head(beaver1, n = 5)
#> day time temp activ
#> 1 346 840 36.33 0
#> 2 346 850 36.34 0
#> 3 346 900 36.35 0
#> 4 346 910 36.42 0
#> 5 346 920 36.55 0
```

It is up to the user to define the appearance of these blocks for LaTeX output.

You may also use: `.rmdcaution`

, `.rmdimportant`

, `.rmdtip`

, or `.rmdwarning`

as the block name.

The R Markdown Cookbook provides more help on how to use custom blocks to design your own callouts: https://bookdown.org/yihui/rmarkdown-cookbook/custom-blocks.html