What is the default page size in a pdf output, and what is the idiomatic way to change it?

knitr
latex
pdf

#1

A basic example of what I believe is the correct approach to setting paper size:

---
title: "letter"
documentclass: letter
output: pdf_document
classoption: letterpaper
---

My writing

Based on documented supported options, and list of LaTeX document classes as well as SO question on needing both params.

My questions are:

  • what is the default page size used in the rmd -> knitr -> LaTeX process?
  • what is the preferred method of accessing other classes and page sized listed in LaTeX docs?
  • why does the above code give me an error of:
! Undefined control sequence.
l.35 \if@titlepage

pandoc: Error producing PDF
Error: pandoc document conversion failed with error 43
Execution halted

?