What's new

## Thursday, November 5, 2009

### Math Blog from the Other Coast

What's new

### Mathematics Study Tips - Banking practice problems

In an actual exam, there usually will NOT be a marker on each problem telling you, for example, that "this problem is from Section 3.2 on the Mean Value Theorem". Instead, all you will see is the statement of the problem (and an implicit promise by the Instructor that the problem falls within the scope of the course). Without the context of which section the problem came from, can you still manage to do the problem? One way to help you to be sure is to take your problems out of the context they are in. Try this:

After each section of a text has been discussed in lecture and you have completed the homework problems for submission, take some time to re-write some of the other section exercises (ones that are "like" the ones in your homework set) in a common place later in your notebook. Add other problems when other sections are completed. Rewrite these problems verbatim from the text, but do not write the section or problem number. Don't DO these problems, just bank them for later.

Now when the exam approaches, and you are looking for items to focus on, go to this section of your notebook, grab 5 or 6 of these "banked" problems, go to a quiet, distraction-less place, and time yourself doing these problems without notes, text, or any other aid. If you can do the problems with ease, you are ready for these types of problems on the exam. If you cannot, however, or if some of them prove difficult, then simply re-orient these problem problems with their original sections and note these sections as ones you still need to focus on. Out of context, these problems are much closer to what you will see on an exam.

Another way to do this is to work with someone else, who can grab a problem from the text without telling you which section it comes from. While this is easier and requires little prior planning, it does involve more than one person. But then again, talking mathematics with others is really how one learns, right?

## Thursday, September 10, 2009

### Math in the Media - The Professional Take

The American Mathematical Society would like to remind you of a special service we offer, Headlines & Deadlines for Students, providing email notification of mathematics news and of upcoming deadlines that are of special interest to both graduate and undergraduate students. These email notifications will be issued about once a month, and when there's special news. Imminent deadlines will be included in these emails, which will link to a web page that's a centralized source for information relevant to students and faculty advisors, atI will add that the news items highlighted on this website may also be of interest to pure enthusiasts of this discipline (and not just students of the field). It's good stuff, and I will be highlighting at times some articles mentioned here. But for now, take a look and sign up if you want the email service.

We hope that you will share this email with the appropriate individuals in your department. It's not necessary to be a member of the AMS to sign up for this email service, at

## Tuesday, July 21, 2009

### Beyond Calculus II: Honors Vector Calculus or not...

We have two flavors of vector calculus here at Hopkins:

110.202 Calculus III and 110.211 Honors Multivariable Calculus

The basic question is; Which should I take?

The basic answer is: depends....

Both of these courses fulfill the same requirements for all majors and minors that require multivariable calculus. Both can serve as prerequisite courses for any higher level course that requires multivariable calculus. Both cover the same basic material over the length of one semester, and run from the basic notions of vectors, matrices and the real space R^n through notions of continuous and differentiable functions of more than one independent variable, ending the basic material with the final major theorems tying together major aspects of the course: Green's, Stokes' and Gauss' Theorems.

The major difference between these two courses is one of focus. 110.202 Calculus III is more of a standard Calculus course, developing a blend of theoretical background on the nature of functions of more than one independent variable and the actual calculations involved in solving problems pertaining to this material. 110.211 Honors Multivariable Calculus, on the other hand, spend much more time on the theoretical nature of the material, digging deeper into the "why" aspects of calculus instead of "how things work". Students in the latter will develop a better understanding of content like the Inverse and the Implicit Function Theorems, and learn better how to analyze functions and problems that are not so straightforward. Furthermore, the honors version goes a bit beyond Gauss' Theorem and 110.202, with an introduction to differential forms, and a basic development of a generalized unified theory of the latter three theorems entitled "generalized Stokes'". Both courses are a challenge, but the latter is more so.

Students getting a BC score of 5 (or a 110.109 grade of B+ or better) can be encouraged to take this version if they are so inclined. Students with less strong scores should stay in 110.202, or at least should inquire further with the Math Department before registering for the honors version. In either case, while 110.211 is indeed a great course in vector calculus, taught the way mathematicians really want to teach a math course, it should be understood that the course will be quite a serious challenge.

Course sizes typically run over 100 easily for each lecture of 110.202, with about 4 recitation sections of 25 each. In contrast, 110.211 runs with about 40 students in 2 recitation sections.

Though always self-selected, students are usually quite enthusiastic about the honors version. it is also great fun to teach!

Hope this helps....

## Wednesday, July 1, 2009

### Chicken or Egg or ...: Which comes first? CalcIII, LinAlg, or DiffEq?

Is it better to take Calculus III or Linear Algebra first?Throw Differential Equations into the mix, and you get a branching of one's math career into three distinct paths. All three of these courses, at least here at Hopkins, have a full year of single variable calculus as a prerequisite; necessary for technique as well as theory in the case of multivariable calculus (Calculus III) and Differential Equations, and necessary for a sufficient level of "mathematical maturity" in the case of Linear Algebra.

But for many majors, and interests, one must take courses in and well understand two, if not all three, of these topics. So what order makes the most sense?

Its a good question. It turns out, it is not really important....

I am starting a new series about these and other courses under the tag and title "Beyond Calculus II". In this series, I will explain better the idea and focus of these three (and other) courses taken after a full year of calculus is achieved. Here at Hopkins, a large population of our students start their tenure here at this level.

For now, though, let's stick with the topic above. To start:

There is neither multivariable calculus nor differential equations in linear algebra, yet there is a bit of linear algebra in both of the others. In contrast, linear algebra is a more mature course, sometimes requiring more in the way of expanding one's frame of reference mathematically than the other two.That said, we actually took a look at performance among students who took the two courses 110.202 Calculus III and 110.201 Linear Algebra back to back over a two year period (there are quite a few of them). I will pass on the details of this study, but we found that there was no real preferred order to these two, at least as far as ultimate grades go.

Couple this with the fact that any linear algebra found in either calculus III or differential equations is essentially covered within the courses, and any of the three may be taken in any real order. Hence preference for time slots, professors, and/or friends in the course may be of higher priority in your choice than content.

And one last note, our course 110.302 Differential Equations, fairly standard in content with most sophomore-level courses at American universities, is a course in ordinary differential equations (involving functions of one independent variable, in contrast with partial differential equations). One can easily describe this course as Calculus II.5 (weird notation, hih?). It can be viewed as the proper successor to Calculus II, rather than Calculus III. Just sayin....

## Monday, June 15, 2009

### Math in the Media: Math and the City?!?

Though not quite similar to Sarah Jessica Parker (et.al.)'s work, it is a good title.

Here, instead, Mr. Strogatz discusses a couple examples of the mathematics of life that mathematicians tend to see everywhere via their training; patterns, proportions and logical structure that show up again and again in disparate contexts. In this case, Zipf's Law on the frequency of word usage in a language, patterns in economies of scale, similarities in the energy needs of a city based on its size to the energy needs of mammals based on their size all share a remarkable one-ness in their structure. "Spooky" is Steven's word fo it.

Its a good read....

One personal note, though (said with tongue firmly planted in cheek): Steven leads the article with

"One of the pleasures of looking at the world through mathematical eyes is that you can see certain patterns that would otherwise be hidden."Right, he is. Sometimes is seems kinda like what Neo sees at the end of The Matrix (although in our case there is no trace of any sort of messianic behavior, no doubt).

And it is quite a pleasure. That is, when it isn't a curse.

## Wednesday, June 10, 2009

### Sleeping; a good study tip?

Apparently, cramming may not be the right approach to optimizing performance. This article in the Daily Telegraph today by Science Corrrespondent Richard Alleyne,

announces the results of a University of Pittsburgh study that says

a night of "high quality sleep" helps schoolchildren get better exam results - especially in maths.Arguably, the study is small (56 students) and the article quotes another article from the Daily Telegraph who quotes the study. But the results make sense, at least from my perspective.

One caveat: The type of sleep most effective is not long in time, but restful in nature, with few if any awakenings or disturbances. However, knowing one has an exam the next day may be cause enough to make the sleep not so restful, no?

Still.... There is good advice in these results.

### Mathematics Study Tips - Scrimmaging

Now imagine jumping into the middle of a real game filled with people who really know how to play. How will you do in that first game? Not so hot, huh?

Building a skill set in a way in which one can play effectively in a sport such as soccer, tennis, basketball, etc. requires many techniques. But one of the absolutely necessary ones is to scrimmage; practice playing in mock games to get a feel for the competition, put drill skills into practice, adapt technique, and learn to think amidst all the action.

Duh, right?

So how come almost no students study for an exam by actually trying to do never-before-seen problems out of the context of which section they are in and in a timed environment? SCRIMMAGE FOR AN EXAM!?!? Well, why the heck not?

Examinations can be extremely stressful and frustrating. "I know this stuff! I've done problems just like these hundreds of times! But with only an hour to do 6-7-9 problems, I just blank! I must be a terrible test-taker."

I doubt it. Most of us can easily pass a walking test, I believe. But then again, we have been practicing that for a while now, right?

Try this next time: After each section is covered and HW problems done, grab a set of problems from that section which are of the same type as those in the HW assignment. Bank them (write them down without reference to the section they came from). As an exam approaches, take some out and under a specific time limit (10 minutes per problem in a calculus course, maybe?) do the problems without regard to notes, book, or any other source (be smart: do this in a place without ANY distractions).

If you can easily do the problems, then those types of problems are yours to jam on in the exam.

If you cannot, then you know what to study a bit more. In this case, study, wait some time, and then try again on a couple more.

Give it a shot. It's better than re-doing HW problems, or re-reading chapters five times over.

## Tuesday, June 9, 2009

### More Virtual Math!

For the last few years, the Mathematics Department have been running online versions some of our freshman and sophomore level service courses (110.108-9 Calculus I-II, 110.201 Linear Algebra, 110.202 Calculus III and 110.302 Differential Equations). Designed and implemented inhouse, these course run for seven weeks in the summer, co-instructed by two of our graduate students each, and are identical in every other way to the in-class versions we run during the regular semesters. This year's version start this next week, on June 15th.

The design philosophies of these courses center around two fundamental principles:

- The courses sacrifice nothing, both in content and in implementation, from the standard in-class, lecture-based version of the course (which ran concurrently in the summer).
- The courses feature live, online lecturing, as well as live recitation sessions, as a core part of the instruction (currently we are the only implementation of online education using fully interactive and live lecturing, I believe; Tell me if I am mistaken. It's hard to keep up).

The implementation of this endeavor is facilitated by a software package called Elluminate Live! (ELive!), a virtual classroom environment that features (screen shot at right):

- an online virtual whiteboard which acts like a chalkboard.
- streaming audio,
- Powerpoint-style slides that can be superimposed on the whiteboard and written over,
- Classroom attendance moderation,
- full student interaction including notification of a "raised hand", side chatroom (fully monitored by the instructor, voice and/or whiteboard enabling for each students or students,
- full recording of live sessions for asynchronous reviewing later, with time stamps for accompanying notes.

Course document management is handled via the WebCT course management software. Homework is done the old fashioned way, but submitted via fax and/or email and graded electronically, and exams are proctored locally. For more details, see the Math Department's webpage.

Past results have been excellent, and this summer we are offering four of our courses in this format (all of the above with the exception of 110.108 Calculus I). I can provide tons more information is anyone is interested.

Thought I would throw this out there again. Cheers....

## Tuesday, June 2, 2009

Apparently, "mathematician is the best career in America right now", with a median income of over 90K. But really, don't take the word of a monk about how great the monastery is. Take it from the Karl Fendelander. In an article on Yahoo! hotjobs entitled

# "The Hottest $40-an-Hour Careers"

Mathematician rates up there with Art Director, Geoscientist, Computer Software Engineer and Pharmacist. Go figure!!Here is the relevant entry:

From an insider, to be honest, the career can cause awkward silences at cocktail parties ;-) .

MathematicianThis career has numbers on its side. In their sweeping study of jobs in America, CareerCast [a job search portal] found that mathematicians are at the very top -- that's right, mathematician is the best career in America right now. Mathematicians are extremely satisfied with their jobs, happy with their lives, and, of course, don't mind that $40+ an hour.

A bachelor's degree get you started, but getting any further usually requires a post-graduate degree. From finance to physics, mathematicians find careers in any industry that deals with numbers.

Median Hourly Wage for Mathematicians in 2007:$43.72 ($90,930 yearly)

But its an excellent lifestyle, rated as one of the lowest in stress, and we are in demand.

## Tuesday, May 19, 2009

### New Text....

The new text comes from the same author, and is really simply the expanded version of the same material. It is "Single Variable Calculus: Early Transcendentals" (ISBN-13: 9780495011699).

The summer courses will continue to use the old text. Sorry for the inconvenience. This new choice will be stable for a while, we believe.

## Thursday, May 7, 2009

### Back again, eh?

After a long hiatus, I decided to begin posting here again. There were reasons for the gap in attendance on my part. But I do notice that some posts are read long after their birthdate, and people do find their content useful. So I will start up again and continue to post on current events, mathematics issues, and department-related matters. For instance, we have started a Facebook group devoted to matters concerning the department. To see it, you will need FB access. Just do a search on our data.

Also new, we will again be changing the textbook for our course sequence 110.108-9 Calculus I-II (Eng. & Phys. Sci.). The author will be the same as the previous book (James Stewart), but we will be using the expanded version. When I get the ISBN, I will pass it along.

Talk to you soon.