R Analysis Report with Sweave/Knitr + Emacs + AUCTEX

1. In Emacs, compose a file "test.Rnw". 

\documentclass{article}  
\title{Test}
\begin{document}  

You can write inline expressions like $\pi=\Sexpr{pi}$.

Here is a code chunk.
<<a>>=
x <- rnorm(100)
summary(x)
plot(x)
@ 

\end{document}

2. Enter command for knitting: "M-n r" (Noweb => Sweaving/Tangling => Knit)
3. Enter command for generating PDF report: "M-n P". 
4.