This course seeks to make calculus rigorous. To do so, we'll prove the main theorems you learned and used in calculus (e.g., the Fundamental Theorem of Calculus) and also make rigorous various concepts and methods you learned in calculus. (Case in point: the notion of a limit.)
This course begins with a lesson on proofs, followed by a few lessons that build up to constructing the real numbers. We then introduce functions and explore the concept of countability, which quantifies how many elements a set contains. Next, we study n-dimensional Euclidean space (R^n) and its associated standard topology. This portion of the course rigorizes what we meant by "open" and "closed" intervals in calculus. We then study sequences, and after that, begin applying what we've learned to rigorize the main calculus pillars: limits, differentiation, and integration.
This is a proofs-based course, and it assumes you have some training in proofs and proof-writing. The prerequisites for the course are Multivariable Calculus (Math 205 at Wellesley) and Linear Algebra (Math 206 at Wellesley).
The course is divided into the following seven units.
This unit begins with a lesson on proofs, and then proceeds to begin the journey towards constructing the set of real numbers. Along the way, we study several proof types (e.g., proof by contradiction) and practice using them to prove facts about natural numbers, rational and irrational numbers, and the set of real numbers.
In this unit we formalize the notion of a function familiar from precalculus, and then introduce a concept -- countability -- that helps us compare the sizes of two sets ("size" understood as "number of elements in"), called the cardinality of a set. One surprising consequence of this development: while the natural numbers, integers, and rational numbers all have the same cardinality, the set of real numbers has a different cardinality.
This unit studies the geometry and topology of R^n, n-dimensional Euclidean space. We begin by studying R^n as a metric space (a space equipped with a measure of distance between two points), and then move on to using the "natural" metric (the Pythagorean distance familiar from R^2) to define open n-balls. We then study R^n as a topological space, with those n-balls forming the "basis" of that topology. Later lessons then use these concepts to generalize the notion of open and closed intervals to the setting of R^n, and study various limit-like notions that appear as topological concepts (e.g., accumulation points). The last four lessons focus on compactness, which generalizes to R^n the properties of closed intervals in R that are foundational to some of the main results in calculus (e.g., the Extreme Value Theorem).
This unit begins to apply the topological concepts developed in Unit 3 to infinite sequences, a familiar concept in calculus and, as we'll see in the next unit, a foundational concept in real analysis. After defining sequences, we'll connect the limit point of a sequence (the point a sequence converges to) to adherent points and accumulation points. We'll then end by discussing Cauchy sequences and their relationship to completeness and compactness.
This unit starts the journey of rigorizing calculus in earnest. First, we define the notions of limit and continuity, and do so from various perspectives (e.g., the sequential perspective; the topological perspective). We then proceed to make rigorous (and generalize) the Extreme Value Theorem. We also relate the results to a new topological concept called homeomorphisms. Next, we rigorize the Intermediate Value Theorem. In so doing, we introduce the notion of connectedness to help us describe the ``doesn't skip any of its image values'' conclusion of the Intermediate Value Theorem. We end with a lesson on uniform continuity, a special type of continuity that will help us rigorize Riemannian integration in Unit 7.
This penultimate unit we'll study differentiation. Starting with the limit definition of the derivative, we'll prove various facts about derivatives you learned in calculus. We'll then connect the derivative to local and global extrema, and prove an important theorem we'll later use to prove the Fundamental Theorem of Calculus: the Mean Value Theorem.
This final unit in the course rigorizes the integration portion of Calculus 1. We'll begin by defining what it means to be integrable and then proving the Integrability Criterion, which converts the definition of integrability into a condition involving epsilon. Then, in Lesson 27 we'll use that Criterion -- along with prior results we've proven in the course -- to prove the Fundamental Theorem of Calculus, thereby connecting integration and differentiation.
This course has been designed to achieve the following learning outcomes by the time you complete the course.
Foundational Knowledge: You will recognize, understand, and develop intuition for new mathematical concepts rooted in real analysis.
Teamwork: You will learn how to engage in and facilitate open dialogue with classmates and others about mathematics, in ways that are respectful of differences and establish equitable learning environments.
Learning How to Learn: You will learn about the latest research on cognitive science and how it can help you become a better student. You will also learn how to pinpoint your areas of academic struggles and develop a plan for resolving them. Finally, you will learn how to become a more independent learner.
Though the vast majority of the course's content will come from the lesson notes I've prepared (these are accessible via the lesson links above), the homework for most of the lessons comes from the book Mathematical Analysis, Second Edition, by Tom Apostol.
If you are currently enrolled in this course with me then you've received a copy of the course's syllabus. It details the additional course policies and the course structure. For everyone else, the short story is that this course is structured in a somewhat flipped classroom format, with a mastery grading scheme for assessments. I wrote about this duo in detail in an article I published in 2020 in a mathematics education journal, but here are the takeaways:
Students read through the lesson notes before class sessions start (you can find these inside the Unit links above).
They then submit reflections on what they learned, which include questions about summarizing what they learned.
During class sessions I review the lesson, fill in the missing portions (these appear in boxes in the notes that say "See Class Notes"), and answer questions. We then work together on the homework in small groups.
Students are assessed using a mastery grading scheme I call Second Chance Grading. In short, biweekly quizzes test for understanding, and rather than have midterms, we have Second Chance Assessments. On these assessments, students can re-attempt previous quiz exercises, and if they score higher the second time around, they receive that new (higher score).
This structure is backed by the latest research on growth mindsets, mastery learning, and the "testing effect." (I discuss all that research in my article on Second Chance Grading.)
If you're ready to get started with the course, click on the Lesson 1 link above. At the bottom of that page -- and all other lesson pages -- you'll find navigation buttons that will help you advance and go backward between lessons.
I hope you enjoy the course. If you happen to catch any errors or have other feedback, please feel free to email me: ofernand@wellesley.edu.