Intro to Mathematical Reasoning course

This page serves as a resource to my online asynchronous course on Mathematical Reasoning and Proof. Originally, this course was taught as Math 300 at the University of Washington, during the winter quarter 2021. If you are a GWU student, you should really take the version that our department offers: Math 2971! The YouTube playlist for this course is here: https://www.youtube.com/playlist?list=PLoxJTbDttvt5irjK-gD_bemI0IetyR7D6

The textbook used was Mathematical Reasoning: Writing and Proof, by Ted Sundstrom, available for free on the author’s website: https://scholarworks.gvsu.edu/books/9/.

On this page, I have posted my own course notes as well as the problem sets that I used. With these free resources, I hope that you can learn how to read and write mathematical proofs, and the basics of mathematical reasoning. With these fundamentals in place, the world of mathematics education opens up greatly!

Another useful resource is my advice on how to type up mathematics: https://blogs.gwu.edu/robertwon/2021/07/18/how-to-tex-your-homework/

Course Notes
Problem Set 1
Problem Set 2
Problem Set 3
Problem Set 4
Problem Set 5
Problem Set 6
Problem Set 7
Problem Set 8

Advanced Linear Algebra: Tools and Applications course

This page serves as a resource to my online asynchronous course on Advanced Linear Algebra: Tools and Applications. The YouTube playlist is here: https://www.youtube.com/playlist?list=PLoxJTbDttvt4p6zPSy_0zURsJV1kDCqw1

Originally, this course was taught in spring 2021 at the University of Washington. It serves as a course covering various applications of linear algebra, with all of the students having taken an introductory course in linear algebra. The course does not require an abstract proof-based linear algebra, and so is rather computational in nature. Course notes for the first course in linear algebra can be found here: https://blogs.gwu.edu/robertwon/files/2021/07/Combined308Notes.pdf

The course, as taught, was designed by Rekha Thomas and Sam Roven at the University of Washington. As the course notes were written by them, I will not share them. At the George Washington University, I teach a similar course which is a bit more proof-based (with applications sprinkled in), so I have included notes from that course. If you are a GWU student, you should consider taking MATH 3125!

The major component of this course is the problem sets, which are linked below. The University of Washington math department has posted homework help videos for this course, which you can find here: https://sites.math.washington.edu/~m318/

Course Notes from 3125 (a similar course I teach at GWU, though not identical)
Problem Set 1
Problem Set 2
Problem Set 3
Problem Set 4
Problem Set 5
Problem Set 6
Problem Set 7
Problem Set 8
Problem Set 9
Problem Set 10

Linear Algebra Done Right course

This page serves as a resource to my online asynchronous course on Abstract Linear Algebra. The YouTube playlist is here: https://www.youtube.com/playlist?list=PLoxJTbDttvt7ny0WEJHWw6-0Sjx7EImIQ

Originally, this course was taught in summer 2020 at the University of Washington. It serves as a second course in linear algebra, with all of the students having taken an introductory course in linear algebra which was more computational in nature. Nevertheless, the mathematically mature student could take this as a first course in linear algebra. The most recent version of Axler’s textbook, Linear Algebra Done Right is now available free on his website: https://linear.axler.net/

Linear algebra is an incredibly powerful subject which is used throughout mathematics, statistics, engineering, computer science, data science, machine learning, and economics. If it feels like I am overstating the power of linear algebra, I would say it is more likely that I’m understating it—there are far more applications of linear algebra than I have time to understand. If you can understand linear algebra conceptually, computationally, and geometrically, then you will be able to use it in whatever application you care most about!

Together with the free textbook, the free YouTube playlist, and the free course materials posted below, I hope that you are able to learn linear algebra in a deep conceptual way no matter your age, location, job, interests, or state in life.

Course Notes
Problem Set 1
Problem Set 2
Problem Set 3
Problem Set 4
Problem Set 5
Problem Set 6
Problem Set 7
Problem Set 8
Midterm Exam
Final Exam

How to TeX your homework

The TeX template used in the video is included at the bottom of this post. You can paste this into a .tex file locally, or into Overleaf.

  • If you’re just starting out, I recommend using Overleaf as your TeX editor.
  • You can use Detexify to hand-draw a symbol to find the LaTeX command for it.
  • There is also a nice WikiBook on LaTeXing mathematics.
  • When in doubt, Google is your friend!

You will frequently have problems with TeX which will make the document unable to compile. You should remember to compile often so that you can pinpoint your errors. Here are some things to check.

  • Remember to place math within dollar signs, so $x^2$ typesets as x2.
  • Make sure you have started and ended all environments in the appropriate spots.
  • Make sure you have closed all of your curly braces { }.
  • Check to see if you used a new command that requires a new package.
%% Thanks to Bennet Goeckner for giving me his TeX template, which this is based on. 
%% These percent symbols tell the compiler to ignore the remainder of a given line.
%% We use them to write comments that will not appear in the finalized output.

%% The following tells the compiler which type of document we're making.
%% There are many options. ``Article'' is probably fine for our class.
\documentclass[12pt]{article}

%% After declaring the documentclass, we load some packages which give us 
%% some built-in commands and more functionality. 
%% The following is a list of packages that this file might use.
%% If a command you're using isn't working, try Googling it -- you might need to add a specific package.
%% I have included the standard ones that I like to load.
\usepackage{amsmath}
\usepackage{amsthm}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{enumerate}
\usepackage{graphicx}
\usepackage{mdframed}
\usepackage{multicol}
\usepackage{verbatim}
\usepackage{tikz}
\usepackage[margin = .8in]{geometry}
\geometry{letterpaper}
\linespread{1.2}

%% One of the nicest things about LaTeX is you can create custom macros. If  there is a long-ish expression that you will write often, it is nice to give it a shorter command.
%% For our common number systems.
\newcommand{\RR}{\mathbb{R}} %% The blackboard-bold R that you have seen used for real numbers is typeset by $\mathbb{R}$. This macro means that $\RR$ will yield the same result, and is much shorter to type.
\newcommand{\NN}{\mathbb{N}}
\newcommand{\ZZ}{\mathbb{Z}} 
\newcommand{\QQ}{\mathbb{Q}}

%% Your macros can even accept arguments. 
\newcommand\set[1]{\left\lbrace #1 \right\rbrace} %% In mathmode, if you write \set{STUFF}, then this will output {STUFF}, i.e. STUFF inside of a set
\newcommand\abs[1]{\left| #1 \right|} %% This will do the same but with vertical bars. I.e., \abs{STUFF} gives |STUFF|
\newcommand\parens[1]{\left( #1 \right)} %% Similar. \parens{STUFF} gives (STUFF)
\newcommand\brac[1]{\left[ #1 \right]} %% Similar. \brac{STUFF} gives [STUFF]
\newcommand\sol[1]{\begin{mdframed}
\emph{Solution.} #1
\end{mdframed}}
\newcommand\solproof[1]{\begin{mdframed}
\begin{proof} #1
\end{proof}
\end{mdframed}}
%% A few more important commands:

%% You should start every proof with \begin{proof} and end it with \end{proof}.  
%%
%% Code inside single dollar signs will give in-line mathmode. I.e., $f(x) = x^2$ 
%% Code \[ \] will give mathmode centered on its own line.
%%
%% Other common commands:
%%	\begin{align*} and \end{align*} -- Good for multiline equations
%%	\begin{align} and \end{align} -- Same as above, but it will number the equations for easy reference
%%	\emph{italicized text here} and \textbf{bold text here} are also useful.
%%
%% Some very specific mathmode commands and their meanings:
%%	x \in A -- x is an element of A
%%	x \notin A -- x is not an element of A
%%	A \subseteq B -- A is a subset of B
%%	A \subsetneq B -- A is a proper subset of B
%%	x \equiv y \pmod{n} -- x is congruent to y mod n. 
%%	x \geq y and x \leq y -- Greater than or equal to and less than or equal to 
%%
%% You'll probably find lots of relevant commands in the question prompts. Also Google is your friend!

\begin{document}
\noindent Your name! \hfill  The date 

\begin{center}
  {\large Math 300 Homework 1}
\end{center}


\begin{enumerate}
\item This is question 1. Note that the \texttt{enumerate} environment creates a numbered list. 

\sol{In the preamble, I created a command which gives a framed box around a solution.
}

\item Here's the next item in the list.
\begin{enumerate}
\item This question might have multiple parts. Perhaps the first part is just computational.
\sol{Here is my answer to part (a). We have that $\int 2x \, dx = x^2$. Or perhaps I want an equation on its own line:
\[ \sin^2(x) + \cos^2(x) = 1.
\]
Maybe I want to \emph{emphasize} some text.
}

\item Maybe the next requires a proof. I created a command which invokes the \texttt{proof} environment built into one of our packages. It includes a box at the end of it.
\solproof{Here is my proof for part (b).

Remember that Google is your best friend for \LaTeX{} questions, but I'm also happy to answer any questions you have! In the notes and in lecture, I will try to point out any new commands I am using.}
\end{enumerate}
\end{enumerate}
\end{document}