=====Morgan's Real Analysis Review Page===== ====Number systems:==== **1-5) What are real numbers, anyway? Why do we need them? How can we rigorously define (ie, construct) them? What are some properties of $\R$ that other number systems don't have? And, by the way: what are some properties of $\N$ that we use in real analysis (perhaps sometimes taking them for granted)? ** ====Sets, sequences, series...==== **6) What's the difference between sets, sequences, and series??** **7)What's a Cauchy Sequence?** **8) How can you tell if a sequence converges (and, if it does, how can you tell what it converges to)? ** **9) How can you tell if a series converges (and, if it does, how can you tell what it converges to)? ** **10)What is radius of convergence?** **11) Why do we care about monotone sequences?** ====Topology:==== **What's a metric space?** ** What are some familiar and less familiar metrics (distance functions)?** ** What are some examples of functions that aren't distance functions, even though they have some properties in common with distance functions?** **What's a complete metric space?** **What are topological spaces, and how is this notion different from that of a metric space?** **Topological concepts are intuitive... until they're not. What are some caveats to watch out for?** **Which properties of topological subspaces depend on the ambient space, and which do not?** **Compact vs closed & bounded: when are these equivalent? When are they not equivalent?** **What does "sequentially compact" mean, and when is this property equivalent to compactness?** **What's so special about compact sets? (Ie, what are some theorems we proved about compact sets that won't hold for other kinds of sets?)** **What is the Heine-Borel Theorem? When can we apply it, and when should we not apply it?** **What is the Bolzano-Weierstrass Theorem, and how does it relate to the Heine-Borel Theorem?** **What are some of the particularly useful results in this section?** ====Continuity:==== **What's a continuous function?** ** What conclusions can we make if we know a function is continuous?** ** What conclusions might we be tempted to make about continuous functions that actually aren't true? ** **What is uniform continuity?** ====Sequences of Functions:==== **What is the difference between pointwise and uniform convergence?** ** What are some examples of sequences of functions that converge pointwise but not uniformly?** **What conclusions can we make about uniformly converging sequences of functions that would no longer necessarily be valid if we replaced uniform convergence by pointwise convergence?** **What conclusions might we be tempted to make about uniformly converging sequences (of functions) that aren't actually true? ** ==== Derivatives:==== **What are some of the key theorems in this section?** **What are some surprising results in this section?** **When do Taylor series approximations fail?** **What is Taylor's Theorem, and why is it useful?** ====Integration:==== ====Extras:==== Note: The following questions appeared on Anton's review page (which I found very useful!). I found them too important to omit, and too well-stated to paraphrase. The two exam-related questions were ones that I did not get right on the midterm. ** What is the Weierstrass M-Test?** ** Why is the set $[0,1] \cap \mathbb{Q}$ not compact while $[0,1]$ is? (MT2, Q1, (4))** ** Why is the set $\{0\} \cup \{1/n | n \in \mathbb{N}\}$ compact? (MT2, Q1, (5))** ====Bonus Questions:==== **What were some of the particularly surprising, memorable, and fun things I learned in this course?** **Briefly list the most significant concepts/theorems covered in this course.** **Where can I find some sample exams to do for practice?** ** Topics Covered (with key definitions & theorems):** (This is a work in progress, and organization will improve soon!) 1) Number systems: $\N$, $\Z$, $\mathbb Q$, $\R$, $\C$, others, & some of their properties Archimedian Property (Something we regrettably skipped: Dedekind's construction of $\R$ from $\mathbb Q$) 2) Max, min, upper bound, lower bound, sup, inf defined. Completeness Axiom of $\R$: Every nonempty subset of $\R$ that's bounded from above has a least upper bound in $\R$ (+ analogous result for greatest lower bound) Sequences and their limits (epsilon & N definition of limit) Some nice theorems about properties of limits, which we can use in lieu of the epsilon & N definition to quickly establish convergence (or non-convergence) . . . Cauchy sequences defined Monotone sequences Theorem: All bounded monotone sequences are convergent. Theorem: As it turns out, Cauchy sequences are precisely the sequences that converge - i.e., we can use the Cauchy criterion as an equivalent definition of convergence. (Sometimes one definition is easier to work with than another in writing a proof, so this is good news). lim inf, lim sup of a sequence (Thm: all bounded sequences have them) Recursive sequences, & tricks for finding their limits, if extant (see Feb 4 note) (cobweb diagram) Subsequences: Every convergent sequence has a monotone subsequence