MAT 21A-A: Answers to Frequently Asked Questions

Questions about email

1. All administrative emails should be directed to the lead TA at rthomas@math.ucdavis.edu.
2. All emails to Professor Vazirani must contain 21A in the Subject.
3. Emails whose answers are given on this webpage or the course webpage will rarely be answered.

Questions about attendance

1. For those of you who skip lecture, you do so at your own risk and are completely responsible for material covered, by, for instance, contacting fellow students.
2. Those who skip section risk missing quizzes, though we will try to announce quizzes ahead of time.
   • The first quiz will be in section on October 6.
3. If you are on the waitlist, we suggest you do not skip section as attendance may be a factor in eventually getting off the waitlist.

Questions about waitlists/fees

1. Make sure your student fees are paid or you will be dropped. This refers to fees you owe to UC Davis; there are no fees specific to this course or Webwork.
2. We have no control over the waitlist. Professors cannot give out PTAs. Your add/drop status is handled by the registrar until October 9; after that time it is handled by staff in 1130 MSB.
3. If you are on the waitlist, then as far as the class is concerned you should do everything that you would do if you were registered (e.g., do homework, attend lecture, attend discussion, take quizzes, take exams).

Questions about homework in general

1. After you submit your homework, we will automatically know. You do not need to email us this info; Webwork will keep track of your score.
2. Correct answers will be released after the due date.
3. To find out how to log in to Webwork, visit this page.
4. If you click on the "Grades" link in Webwork, you will notice that every problem you have completed says "C" above it. Here, "C" stands for "correct"; it is not a letter grade.
5. Some homework questions may come from the textbook. YOU are responsible for obtaining access to a current edition of the textbook for problems such as these, for example by asking a friend or checking in the library.
6. When entering answers into Webwork, some web browsers may fill in something other than what you have typed. Be careful! If this happens to you, I will not be able to give you any extra chances to submit your answer unless you can somehow PROVE to me that this is what actually happened. To avoid this issue, you can turn off your web browser's "autocomplete" feature or uncheck the "remember what I enter in forms" checkbox, depending on your browser.
7. If a homework's due date has passed but you would like to do a problem anyway for practice (say, while studying for an exam), Webwork will let you do this. Enter your answers and click "Check Answers". Doing this will NOT affect your grade on that homework assignment! If you submit a correct answer once, then go back and enter an incorrect answer, Webwork will remember to give you credit even as it tells you that your current answer is incorrect.
8. Even if a homework is not due yet, if you have used up all your attempts on a problem but want to try it anyway, Webwork will let you do this. You won't get credit for any correct answers you submit after you use up all your attempts, but you can find out whether your answers are correct or not.
9. Webwork uses its own clock, which may be a few minutes off from your clock. You are responsible for submitting your answers before Webwork thinks they are due. If you want to see what time Webwork thinks it is, reload your webpage and scroll down to the bottom for "Page generated at" in small letters. The time listed there is the time Webwork thought it was at the moment you reloaded the webpage.

Questions about specific homework problems

1. For problem 4 of homework 2, there is a subtle issue with the way Webwork checks your answers which means that you may be told that your formula for h(x) is correct when it is actually only almost-correct. Think carefully about what the domain of h(x) should be. If you have trouble, you might ask your TA for help during discussion section or office hours.
2. Everyone automatically received credit for the last problem on homework 8. But there is a similar problem on homework 9 for which you will not receive credit unless you complete it correctly.

Questions about exams & final grades

1. The textbook is an excellent source of practice problems.
2. You are responsible for everything in the chapters covered (for the first midterm, chapters 1 and 2). Rather than being able to recite theorems and definitions, it is more important that you understand what they mean and how to use them. But you are expected to know all theorems and definitions.
3. You will be expected to show work; therefore if you use a rule or theorem or definition you should know which rule or theorem or definition it is.
4. After exams have been graded, you can find rough curves through the course website at http://www.math.ucdavis.edu/~vazirani/F09/21exams.html#exams.
5. If you find that you are not doing as well on exams as you had hoped, here are some tips:
   • Visit your TA, Professor Vazirani, someone in the Learning Skills Center, or a tutor to go over old exams and figure out what you got wrong and why.
   • Try making your own practice exams and take them with a time limit. You can find practice problems in the review section of the textbook.
   • Study with a friend!
   • When taking practice exams, be sure to do them with time pressure, and actually write out solutions instead of convincing yourself that you know how to do the problems and skipping them.
   • Remember that you have the option of having the final weighted more heavily than the midterms. The gradebook will do this automatically if it is better for you.
6. If you are worried about passing the class:
   • On the course website you can see a breakdown of grades and how to figure out your overall percentage. This means that you can figure out yourself how well you ned to do on midterms and finals in order to pass the course.
   • There may be a curve, but you should do your calculations on the assumption that there will not be one.
   • It's probably safe to assume that a passing percentage will be around 65%, give or take a few. If you get Bs on the second midterm and the final, you are pretty likely to pass; do be aware though that this course moves quickly and if you fall behind it can be tough to catch up.
7. The final exam is comprehensive, but more heavily weighted toward material since the second midterm. Note that we did NOT cover sections 4.7 and 4.8 in this course.
8. Math grad students are holding a tutoring fundraiser on Saturday, December 5 from 10 AM to 5 PM in MSB 1147. The cost is $10 for the entire day.
9. You DO need to know formulas like those giving the volume and surface area of spheres, cylinders, boxes; the volume of cones; and the area and perimeter of rectangles, triangles, and circles.
10. The final exam is on Tuesday, December 8 from 3:30-5:30 in our usual classroom, 1001 Giedt.

Questions about mathematical content

1. On continuity: following the definitions of "continuous" and "discontinuous", if f(x) is not defined at a point x=c, then f(x) is discontinuous at that point. More subtlely, if f(x) is continuous at every point in its domain, then f(x) is a continuous function. For example, f(x)=1/x is not continuous at x=0 since 0 is not in its domain, but it is a continuous function since it is continuous at every point in its domain.
2. For problem 7 of homework 5, option B is better than option A because since the limit does not exist, there's no way to even compare it to f(a).
3. If a function is increasing on an open interval and an endpoint of the interval is in the domain of the function, then it is preferable to say that the interval where the function is increasing INCLUDES the endpoint. For example, if f is increasing on (1,2) and 1 and 2 are in the domain of f, then it is better to say that f is increasing on [1,2].
4. Every absolute extremum is also a local extremum (but not the other way around). Endpoints CAN be critical points, but not every endpoint is a critical point and not every endpoint is a local extremum. In general a local maximum occurs at x=c if for x a little to the right and left of c we have f(x) < f(c). If we're at a left endpoint, we don't need to check the x to the left, only to the right.