01-intro.Rmd

# Introduction {#intro}

```{r setup01, include=FALSE,cache=FALSE}
knitr::opts_chunk$set(dev = "png", dev.args = list(type = "cairo-png"),
                      fig.align='center', cache = TRUE,tidy=TRUE)
```

This is now chapter 2 (maybe an introduction). 

We can use the usual Rmarkdown tricks. 

```{r}
## so we can write
2+2
```


You can write citations, too. For example, we are using the **bookdown** package [@R-bookdown] in this sample book, which was built on top of R Markdown and **knitr** [@xie2015]. 


```{r include=FALSE}
# automatically create a bib database for R packages
knitr::write_bib(c(
  .packages(), 'bookdown', 'knitr', 'rmarkdown'
), 'packages.bib')
```