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Math 1365 (Introduction to Mathematical Reasoning), Fall 2022



Course Information
Instructor Class Times Office Hours
Evan Dummit
edummit at northeastern dot edu
MWR 4:35pm-5:40pm
Richards 254
MW noon-1:00pm
MWR 3:00pm-4:00pm
Online, via Zoom
This section of Math 1365 is a more intensive pilot program for a new course being developed. For detailed information about the course, please consult the 1365 Course Syllabus. (Note: any information given in class or on this webpage supersedes the written syllabus.)
Teaching Assistant Recitation Times + Locations Office Hours
Jose Zamora Orellana
zamoraorellana.j at northeastern dot edu
T 1:30pm--4:30pm
750 Behrakis
F 11:00am--12:30pm
141 Ryder
By appointment
463 Lake
We will use Piazza for any course-related discussion: here is the Piazza page.
All homework assignments will be posted on this webpage (see below).
Homework assignments will be collected via Gradescope on Canvas. Please submit scans of your homework pages by 11:59pm Eastern on the due date. Late assignments may be penalized at the grader's discretion.
The instructor will write lecture notes for the course (see below) to supplement the official textbook as the semester progresses. The course will generally follow the presentation in G. Chartrand's "Mathematical Proofs: A Transition to Advanced Mathematics", but it is not necessary to purchase the textbook for this course.
The final exam is on Tuesday December 13th from 3:30pm-5:30pm in Knowles 010. Please plan to arrive at least 5 (preferably 10) minutes early.


Homework Assignments
Some Tips on Problem Solving are available as suggestions for the written assignments.
Homework #1, due Tue Sep 13th. (solutions)

Homework #2, due Tue Sep 20th. (solutions)

Homework #3, due Tue Sep 27th. (solutions)

Homework #4, due Tue Oct 4th. (solutions)

Homework #5, due Tue Oct 11th. (solutions)

Homework #6, due Tue Oct 25th. (solutions)

Homework #7, due Tue Nov 1st. (solutions)

Homework #8, due Tue Nov 8th. (solutions)

Homework #9, due Tue Nov 15th. (solutions)

Homework #10, due Thu Dec 1st. (solutions)

Homework #11, due Thu Dec 8th. (solutions)


Handouts / Lecture Notes
Handout Topics
Chapter 1: Proofs, Logic, and Sets (28pp, v2.00, posted 9/1) 1.1 ~ Overview of Mathematical Proof
1.2 ~ Elements of Logic
1.3 ~ Sets and Set Operations
1.4 ~ Quantifiers
Chapter 2: The Integers and Modular Arithmetic (20pp, v2.00, posted 9/22) 2.1 ~ The Integers, Axiomatically
2.2 ~ Induction
2.3 ~ Divisibility and the Euclidean Algorithm
2.4 ~ Primes and Unique Factorization
2.5 ~ Modular Congruences and The Integers Mod m
Chapter 3: Relations, Orderings, and Functions (22pp, v2.10, updated 10/24)
(updates in v2.10: added construction of Q to end of 3.2.2, added examples to end of 3.4.4)
3.1 ~ Relations
3.2 ~ Equivalence Relations
3.3 ~ Orderings
3.4 ~ Functions
Chapter 4: Cardinality and Countability (13pp, v2.00, posted 11/3) 4.1 ~ Cardinality and Countability
4.2 ~ The Pigeonhole Principle
Chapter 5: Elements of Algebra (16pp, v1.00, posted 11/21) 5.1 ~ Groups
5.2 ~ Fields


Exam Information
Exam Date, Time, Location Topics Review Material
Midterm 1
Exam (sols)
Thu, October 13th
In Class
Homeworks 1-5
Notes §1.1-2.4
Midterm 1 Review Problems (answers)
In-class review Wed Oct 12th
Midterm 2
Exam (sols)
Thu, November 17th
In Class
Homeworks 6-9
Notes §2.5-4.1.2
Midterm 2 Review Problems (answers)
In-class review Wed Nov 16th
Final Tue, December 13th, 3:30pm-5:30pm
Knowles 010
The final is COMPREHENSIVE!
Homeworks 1-11
Notes Chapters 1-5
Final Supplementary Review Problems (answers)
Review sessions TBA
Bring your University ID to all exams. You are allowed a calculator and a 1-page 8.5in-by-11in double-sided note sheet, but no other aids beyond writing implements during exams.


Tips For Success In This Course
Attend Lecture Missing lecture is a very bad idea! If for any reason you cannot make it to a class, you should watch the lecture recording and review notes from someone who did attend. You are responsible for all material covered in lecture.
Read the Lecture Notes (or Textbook) The lecture notes and the textbook are comprehensive sources of material for the course. The notes are intended as review material, although many students like to read them as preparation before attending the lecture on the corresponding topics. Please note that the electronic notes are not identical to the material covered in class: this is by design, so as to provide you a slightly different perspective on the material.
Solve Homework Problems Much of the learning in this course will take place as you solve the homework problems. Like many other activities, problem-solving and proof-writing are things that are learned by doing them, not by hearing someone else tell you about them or reading about them in a book. As such, the homework assignments are an integral part of the course, and are fundamental to learning the material. It is highly recommended that you look over the homework assignments as soon as they are available, and work on them well in advance of the deadline: many problems will take substantial time and effort to solve, and you should expect to spend as much time as you need to finish the assignments.
Attend Office Hours Office hours are specifically reserved for you to receive individual, one-on-one help from the instructor. Office hours will be the most effective when you have already put in effort to learn the material on your own (including trying to solve the homework problems), and when you come in with a list of specific questions or topics you are struggling with.
Attend Problem Sessions There are two weekly problem sessions run by the course's TA. The goal of the problem session is to provide you a location where you can work with other students on assignments, and also get assistance from the TA. It is highly recommended to attend one of the problem sessions each week to work on the homework problems.
Use Tutoring Services The university offers a wide variety of (free) tutoring services. Please consult the Northeastern Tutoring page for additional information on peer tutoring. The Math Tutoring Center, located in 540B NI, is specifically set up for tutoring in mathematics courses. Tutoring appointments can be made via MyNEU (which will provide lists of available appointments for the tutors for your specific classes); walk-in tutoring is very limited and tends to be unavailable near exam dates.


Course Schedule
The schedule is subject to change! All sections refer to the course lecture notes.
Week Schedule
Week of Sep 5
(class starts 9/7)
§1.1: Overview of Mathematical Proof
§1.2.1: Propositions and Conditional Statements
§1.2.2: Boolean Operators and Boolean Logic
No homework this week.
Week of Sep 12 Homework #1 due Tuesday 9/13 on Canvas.
§1.3.1: Sets
§1.3.2: Subsets
§1.3.3: Intersections and Unions
Week of Sep 19 Homework #2 due Tuesday 9/20 on Canvas.
§1.3.4: Complements and Universal Sets
§1.3.5: Cartesian Products
§1.4.1: Variables and Quantifiers
§1.4.2: Properties of Quantifiers
Week of Sep 26
Homework #3 due Tuesday 9/27 on Canvas.
§1.4.3: Indexed Sets
§2.1: The Integers, Axiomatically
§2.2.1: Induction
§2.2.2: Examples of Induction
Week of Oct 3 Homework #4 due Tuesday 10/4 on Canvas.
§2.3: Divisibility and the Euclidean Algorithm
§2.4: Primes and Unique Factorization
Week of Oct 10
(no class 10/10)
Homework #5 due Tuesday 10/11 on Canvas.
Review for Midterm 1.
MIDTERM 1 in class Thursday 10/13
Week of Oct 17 §2.5: Modular Congruences and Modular Arithmetic
§3.1: Relations
No homework this week.
Week of Oct 24 Homework #6 due Tuesday 10/18 on Canvas.
§3.2.1: Equivalence Relations
§3.2.2: Equivalence Classes
§3.3: Orderings
Week of Oct 31 Homework #7 due Tuesday 11/1 on Canvas.
§3.4.1: Functions
§3.4.2: Function Composition
§3.4.3: One-to-One and Onto Functions
Week of Nov 7 Homework #8 due Tuesday 11/8 on Canvas.
§4.1: Bijections, Cardinality
§4.2: Countable and Uncountable Sets
Week of Nov 14 Homework #9 due Tuesday 11/15 on Canvas.
§4.3: Infinite Cardinalities
Review for Midterm 2.
MIDTERM 2 in class Thursday 11/17
Week of Nov 21 (no class 11/23-11/27) §4.4.1: The Pigeonhole Principle
§4.4.2: Pigeonhole Arguments
No homework this week.
Week of Nov 28 §5.1.1: Groups
§5.1.2: Dihedral Groups
§5.1.3: Symmetric Groups and Cycles
§5.1.4: Subgroups and Orders
Homework #10 due Thursday 12/1 on Canvas.
Week of Dec 5
(class ends 12/7)
§5.1.5: Lagrange's Theorem
§5.2: Fields and the Real Numbers
Homework #11 due Thursday 12/8 on Canvas.
FINAL EXAM on Tuesday December 13th from 3:30pm-5:30pm, Knowles 010