Can't knit in R markdown

Question

Recently I was doing a course in Coursera and faced the problem while doing R markdown. When I run the code in the console it works just fine however, when I knit it, the rmarkdown only show text in the code chunk as below.

I run this in console and it work just fine:

But when i knit the code appear as text:

When I hit the green arrow it appears like there are some error going on:

Answer 1

The bottom screenshot you provided is not an R code chunk. It does not have the proper header. R code chunks in an R markdown file must be formatted like this:

```{r}
R code goes here
```