# 1 What is this?

This is a book published using the R Markdown language. R Markdown supports Latex, so you can make pretty equations like Professor Kapelner likes: $$a^2 + b^2 = c^2$$. To type inline latex, just surround your code with dollar signs. That was published like this: $a^2 + b^2 = c^2$

You can edit the markdown for this book from RStudio just like you would edit a regular R Markdown (.Rmd) file. Here’s a picture of what it looks like as I edit this book and the R code used to make it (at 1:15 am, oh dear).

knitr::include_graphics("https://i.imgur.com/EOOspRZ.png")

The bookdown package allows you to publish cool looking online web books for free just like this and host them on bookdown on RStudio Connect (this normally costs money, but it’s free for people publishing books). It was invented by Yihui Xie who is the main author of the package that the function that made that picture comes from (knitr). It is one of R’s most popular graphical packages.

To see how this book works and start making changes to it, follow the instructions to get started on bookdown.org: https://bookdown.org/home/getting-started.html

## 1.1 Annotations

Notice that there’s a little arrow to the side of the screen. Click the arrow and see what happens, or just highlight some text on this page, and you’ll notice a little widget comes out that lets you highlight or annotate text.

You’ll need to sign up for hypothesis.is to do this when you’re in the side pane. It’s an open source tool meant to get people to annotate and peer review the internet, including R Markdown books, and you can use it to suggest small changes to this book or discuss its content/ask questions. This video explains it a bit more.