Midterm information for Math 309ABC, Autumn 2012

Midterm Date: Friday, October 26

In addition to the usual Office hours, this week there are extra hours on Thursday:
Prof. Monard 11-12:30 in his office, PDL C-330
Prof. Arms 12:30-2 in her office, PDL C-338.
You can of course email your own instructor for an appointment if you cannot make the scheduled office hours.

General information, rules for notes, etc.

• Hopefully everyone will be healthy and on time for the test, but sometimes emergencies happen. Here is general advice for if you (will) miss a quiz or exam: As soon as you know you will miss (or have missed) a quiz or exam, email your instructor. (If you don't have access to email, call: Prof. Arms at (206)543-9458, Prof. Monard at (206)543-1195, or messages may be left at the Math Department office, (206)543-1150.) If you know ahead of time that you will miss a quiz or exam for a good reason, email a request to take it early, stating your reason. In case your instructor agrees to the request, suggest times you can take the quiz or exam before the rest of the class does.
• Notes. You may bring one notebook (8.5 by 11 inches) sized sheet of handwritten notes. The main reason for allowing notes is to encourage "top down" studying (organizing your thinking about the material, identifying common themes, etc.) and, conversely, discourage "bottom up" studying (merely memorizing formulas). Handwritten notes are required so that you have to think about the material to produce the notes, which is also a good study technique. It's OK to write on both sides of the paper, but it is in your interest to summarize thoughtfully, so you are not spending precious exam time reading through overly detailed notes.
• Only non-graphing calculators allowed. Tests and quizzes are designed to be doable without a calculator, so if you don't have a non-graphing calculator, you don't need to get one. In particular, you should leave answers in "exact" and unsimplified form: if the answer comes out to 2.5 + π - 1/6 - cos(π/3), you should evaluate cos(π/3) but otherwise may leave the answer as is. Do not evaluate trig functions at "nonfamous angles", e.g. leave cos(3/2) as is. Do NOT give a decimal approximation to the answer, because your instructor can figure out your thought process better from the exact answer.
• There will be room on the midterm to work the problems. If you need extra paper, raise your hand.
• Seating at exams. If you arrive early, please help arrange the chairs so that there is room between rows for your instructor to get to students to answer questions. Also, leave the seats in the front row and near the door empty for the people who arrive at the last minute from classes on the other side of campus. During the test, a seating chart may be passed along your row. When you get the chart, on the next blank line, print your name and sign with your usual signature, also, then pass to the next person. The instructor will collect the chart at the end of the row.
• Show your work and/or reasoning (unless the question says you don't have to.) An answer with no justification for how you found it may be worth little or no partial credit. Don't be afraid to use some English as well as symbols.
• A few more test-taking tips: Read instructions carefully, so you don't do more work than you have to. Don't simplify a complicated algebraic expression unless required to (or if it's easier because you need it for the next step). If you do change your answer, cross out rather than erasing. It's quicker, and sometimes your new reasoning is easier to follow if the grader can glance at what you tried first. (Raise your hand if you need more paper.)

Topics covered, study suggestions

• Chapter 7 and § 9.1.
• To prepare for the exam, first do HW 5. Also review any homework or quiz problems you had trouble with. But note that the quiz problems have intentionally been very basic. The test problems will be harder, both because some will be longer and/or more complicated, and because you will be responsible for more topics.
• Next try the sample test posted here. Read the general instructions (so they will be familiar when you actually take the test) and then try the problems BEFORE you look at the solutions (which are now posted at the same site as the sample test). Remember that no single test can include all skills or problem types that you are supposed to know. The test you take may ask questions that require you to use ideas in different combinations than those on the sample test, or even require some ideas not included in the sample.
• Additional recommended practice problems:
  • Additional problems on phase portraits: §7.5, #24-27: classify the type and stability of critical point at the origin (as in §9.1 homework problems), and do a rough sketch of the phase portrait. If our midterm asks you to sketch a phase portrait, only a rough sketch is required. For spiral points and centers, one trajectory with direction indicated is enough. For nodes and saddles, as for the homework, draw the eigenvector trajectories and one trajectory in each resulting region. Any such sketch will count for only a small number of points.
  • Additional inhomogeneous problem: Look at §7.4, problem 6, and its solution in the back of the book. Let x' = P(t)x be the equation in the answer for part (d), and restrict to t > 0. Confirm that the two vector functions given are solutions to this equation. Then find the general solution to x' = P(t)x + [3t t²]^T.
  • The Au11 midterm here. To get full benefit, be careful not to look at the solutions until after you do the problems yourself. In problem 3c, just use the hint (and ignore the question if it confuses you). Also note that the solutions include three techniques for solving problem 2. We did not study the method of undetermined coefficients, and thie method requires practice on multiple problems to use without mistakes. So, unless you read in the book about this method and practiced it on several problems, don't use it.
  • 3-dimensional problems: #1 on Sp10 Midterm here.

Return to the Math 309A Homepage.
Return to the Math 309BC Homepage.
Most recently updated on October 23, 2012