Math21a, Fall 2000 Course Head: Prof. Clifford H. Taubes

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# Math 21a Fall 2000 Course Announcement

The subject: Since Math 21a is a mathematics course, I will start with a digression to introduce a definition for the science of mathematics so as to distinguish it from the other sciences:
 Mathematics consists of the study of all imaginable worlds with the goal of uncovering transcendent, universal relationships and underlying symmetries.
By way of contrast, fields such as physics, chemistry or biology, or even the more social sciences such as economics are concerned, by definition, with the details of the particular universe that we inhabit. This is to say that the charge for the other sciences can be summarized as follows:
 Provide a predictive understanding of the given universe.
The other sciences find mathematics useful, and often remarkably so, because the underlying relationships which transcend our particular context yield predictions which would be unfathomable with a focus that restricts solely to our own world.
With the digression now over and with the preceding remarks as background, consider that Math 21a (and Math 21b as well) focuses on various concrete and abstract properties of 2 and 3 dimensional space. Of particular concern here in Math 21a are functions whose values vary over such spaces. This is to say that the subject is calculus for functions of two or more variables. Such functions arise ubiquitously in the sciences. Here are some examples: First, a biologist might be interested in the concentration of a certain cellular protein as a function of the age of the cell and the distance from the cell's nucleus. In this case, the function measures protein concentration and it depends on the two variables, age and distance. Second, a physicist might be concerned with the strength of a current in a superconductor as a function of the temperature, the strength of the ambient magnetic field and the density of impurities. So here, the function in question depends on the three variables, temperature, magnetic field strength and impurity density. Third, an environmental scientist might be concerned with the concentration of mercury in the Charles River as a function of distance from Boston Harbor and water flow rate. Here, the interest is in a function of two variables, distance and flow rate. Meanwhile, a geologist might worry about a function that gives the height above sea level of the Modoc Plateau in California as a function of the three variables, latitude, longitude and time (measured in units of millions of years). Finally, an economist might be concerned with the Dow Jones average as a function of various other economic indicators.
In any event, our concern in Math 21a is not so much on examples, but on developing various general techniques from calculus for the purpose of analyzing and predicting the behavior of functions of two or more variables. None-the-less, concrete examples abound in the course. However, there are discussions ahead that can seem quite abstract; but be aware that even the most abstract subjects in this course have applications in the other sciences, even if such applications are not mentioned here.
The sections: The precise subjects that are covered in Math 21a depend to some extent on the particular type of section that you choose. In this regard, you should know that Math 21a is taught in small sections of size 25 students, with sections labeled as "Regular", "Physics" and "BioChem". A section without a special label is automatically a Regular section.
• All sections cover at least the following topics: Functions of several variables, differentiation and integration of functions of several variables, parametric curves and surfaces, optimization, vector fields, linear approximations and various topics in partial differential equations.
• The Regular and Physics sections also cover the following: Line and surface integrals, Greens theorem, the divergence theorem and Stokes' theorem. These are the multi- variable generalizations of the Fundamental Theorem of Calculus.
• The Physics sections will use examples drawn from Physics to illustrate some of the covered topics. Certain of the homework problems assigned to this section will also come from Physics.
• Meanwhile, the BioChem sections covers, in addition to the material in the first point, various introductory topics in statistics and probability. Note that there are no specific references to either biology or chemistry in this section. Thus, the material is accessible to all.
Detailed syllabi for the various types of sections are provided below.
Which kind of section should you choose?
• If you contemplate being a physics concentrator, you would benefit by being in the Physics section.
• In any event, if you are planning to take either the Physics 15-16 or Physics 11 sequences, you should enroll in either a Regular or a Physics section.
• If you are planning to concentrate in BioChemical Sciences, then you are strongly urged by that department to enroll in a BioChem section.
• Anyone who will not, at some point, enroll in Physics 11 or 15-16 might consider a BioChem section as well.
To section: If you have an email account, log on to the Harvard computer system, then type 'section' instead of 'pine. If not, use any Harvard computer, telnet to 'fas' and when prompted to 'login', type 'section'. At the password prompt, press 'enter'.
 telnet to fas.harvard.edu
Follow the online instructions from here. If there is a problem with your section assignment, contact Susan Milano in office 308 of the science center. .
Course Head: Clifford Taubes, Science Center 504, email chtaubes@math.harvard.edu . Drop in office hours on Mondays 12-1:30 and Fridays 2-3:30.
Prerequisites: Math 1b with a satisfactory grade, or AB-BC score of at least 4, or scores of at least 20, 8, 4 on the respective three Harvard University Math Placement Tests.
Textbooks: All of the sections require Multivariable Calculus by Ostebee and Zorn with the Student Solutions Manual, published by Saunders College Publishing. The BioChem sections also require Fundamentals of Biostatistics by Rosner, published by Duxbury Press. These books are available at the Harvard Coop.
Class meetings and problem sessions: The first class meeting, which everyone should attend, is on Monday, September 18 at 8am in Science Center Lecture Hall B. Except for this one meeting and for the course wide exams, you meet in your assigned section. The section meets for a total of three hours per week, either one hour each on Mondays, Wednesdays and Fridays, or for one and one half hours each on Tuesdays and Thursdays. Each student is also assigned to a 1-hour math problem session, conducted weekly by a Course Assistant. The meeting time for the problem session will be arranged in your section during the first week of classes. You may attend more than one problem session per week; and the schedule of all problem sessions will be posted on the Calculus Office bulletin board outside of Science Center 308.
Homework: A substantial problem set will be assigned once each week to be turned in as instructed in the subsequent week. You are strongly encouraged to discuss the homework with your fellow students and to form study groups to work these assignments. However, you must write up the solutions by yourself, and you must note the names of your coworkers somewhere on the homework. (This last point is simply a matter of professional ethics.) The lowest homework score will be disregarded when your average homework grade is computed.
The weekly homework assignments will be posted on the Math 21a web site. The answers to the homework assignments will appear after the due date on the web site as well. Moreover, selected problems from the homework will be discussed in the problem sessions. Homework assignments that are submitted after their assigned due date will be accepted at my discretion. In any event, no more than two late homework assignments will be accepted per student over the course of the semester.
In addition to the weekly homework assignment, various problems of a more routine sort will be suggested for the subsequent class meeting. These are not to be turned as their answers are in the Student Solutions Manual. However, you are strongly urged to work them on your own or with others in the class because their purpose is to supply practice with the techniques and ideas that are presented in the lectures. By the way, you are also strongly encouraged to try on your own other problems from the text to hone your ability with the concepts and techniques. Donıt feel that you should limit yourself to the suggested problems. In this regard, note that the Student Solution Manual answers most of the odd numbered problems in the book.
Computer assignments: There will be a few specially designated assignments during the semester whose purpose is to introduce you to graphing and mathematical manipulation computer programs. The use of computer technology to solve mathematical problems is one of the great advances of our age, and so I want all of you to have at least a fleeting introduction to this side of the subject. No prior knowledge of the relevant software technology is required to work these assignments. More details will come later in the semester.
Exams: There are two course-wide midterms and a final. The midterms will take place on Wednesday, October 18 and Wednesday, November 15, both from 7:00-9:00pm in Science Center C & D. Mark these dates on your calendar now, as no make-ups will be given. The final exam is scheduled by the University for a date in mid January. According to the Course Catalogue, the preliminary schedule has the final on Saturday, January 13 in the morning. The University will confirm this date later in the semester.
Grading: Your final grade will be based on your performance on the homework (30%), the computer assignments (3%), the two midterms (10% for the first and 15% for the second), and the final (42%). A small upward adjustment in the grade is possible when the final is dramatically better than the average of the midterms and the homework.
Computers and calculators: The visualization of surfaces and other geometric phenomena is an important aspect of this course. In as much as computerized graphing programs aid you to develop this ability, you are encouraged to employ them as part of the learning process. In this regard, the scheduled computer assignments are designed to introduce you to the tool of computer graphing and mathematical manipulation.
However, be forewarned that for the purposes of this course, computers should be considered solely as an aid to the development of geometric intuition. This course is teaching various concepts whose applications may or may not be facilitated by a computer. However, without a strong understanding of the underlying concepts, the computer wonıt be much use. The point here is that computers can do many things, but they canıt yet think for you. As powerful as todayıs computers are (and tomorrowıs will be), none of us will live to see the day when they can turn pig feed into gold. In any event, the use of computers and other electronic aids will not be permitted during exams. (Bring only your brain and some pencils.) With this in mind, note that various homework problems ask you to sketch or otherwise describe various geometric objects. With the exception of the specially designated computer assignments, you are strongly advised to struggle with these first without electronic aids, as they may be quite trivial with a graphing program.
Words of Caution and Advice: This course will be more demanding then your previous mathematics courses at Harvard and elsewhere. In particular, the assignments will be time consuming and you should plan now to set aside regular hours to wrestle with them. It is virtually impossible to do well in this course without working the homework assignments in a timely fashion. Note also that this course is fast paced, and new material builds on old. Thus, do not fall behind. If you find yourself falling behind, please contact your sectionıs teacher immediately to discuss options for personal help. Indeed, Harvard provides many services along these lines for its students, and your section teacher can help you find them.
When you are working your assignments, keep in mind that your success in this course will require more than just memorizing formulas and "plugging in values". Numerical calculations are still important, but play a smaller role than in 1-variable calculus. Here is the key to success:
 Understand the underlying concepts and then work enough problems so that you can employ them in any example thrown at you.
(In this regard, you will consistently battle with homework and exam problems that differ significantly from material discussed in class.)

# Math 21a Fall 2000 Syllabus Outline

 Regular Sections
 Textbook: "Multivariable Calculus with the Student Solutions Manual" by Ostebee and Zorn,

 Section 1.1: 3-d space and surface. Section 1.2: Parametric curves. Section 1.3-1.4: Vectors, vector valued functions. Section 1.5: Derivatives, anti-derivatives and motion. Sections 1.6-1.7: Dot product, lines and planes Sections 1.7-1.8: Lines, planes and cross product. Appendix C: Introduction to matrices. Sections 2.1 and 1.1: Functions of several variables. Sections 2.2-2.3: Partial derivatives, contours and linear approximations. Sections 2.3-2.4: Linear approximations and the gradient. Sections 2.5-2.6: Theory of derivatives, high order derivatives and quadratic approx. Section 2.7: Max-min, critical points and extreme points. Sections 2.7 and 4.4: More on extreme points, constrained optimization. Section 4.4: Constrained opimization. Section 2.8: Multivariable chain rule. Section 3.1: Multiple integrals. Section 3.2: Calculating integrals by iteration. Section 3.3: Integrals in polar coordinates. Section 3.4: Integrals in spherical and cylindrical coordinates. Section 5.1: Line integrals and vector fields. Section 5.2: The fundamental theorem of line integrals. Section 5.3: Line integrals and Green's theorem. Section 5.4: Surfaces and parameterizations. Section 5.5: Surface integrals Section 5.6: Derivatives of vector valued functions, div and curl. Section 5.7: Stoke's theorem. Section 5.7: Divergence theorem. Section 5.7: More on Stoke's and Divergence Theorems.
 Handouts: Differential equations. Various computer assignments. Two "midterm" exams: Wed., Oct. 18 and Wed., Nov. 15, both are from 7-9pm and in Science Center Lecture Halls C and D. A final exam scheduled by the University; the preliminary date is Sat., Jan. 13 in the morning.

 Physics Sections
 Textbook: "Multivariable Calculus with the Student Solutions Manual" by Ostebee and Zorn

 Section 1.1: 3-d space and surface. Section 1.2: Parametric curves. Section 1.3-1.4: Vectors, vector valued functions. Section 1.4-1.5: Derivatives, anti-derivatives and motion. Sections 1.6-1.7: Dot product, lines and planes Sections 1.7-1.8: Lines, planes and cross product. Sections 1.1, 2.1-2.2: Functions of several variables, partial derivative, gradients. Section 5.1: Line integrals and vector fields. Section 5.2: The fundamental theorem of line integrals. Section 2.3Linear approximations Section 2.4: The gradient and directional derivatives. Appendix C: Introduction to matrices. Sections 2.5-2.6: Theory of derivatives, high order derivatives and quadratic approx. Section 2.7: Max-min, critical points and extreme points. Sections 2.7 and 4.4: More on extreme points, constrained optimization. Section 4.4: Constrained opimization. Section 2.8: Multivariable chain rule. Section 3.1: Multiple integrals. Section 3.2: Calculating integrals by iteration. Section 3.3: Integrals in polar coordinates. Section 3.4: Integrals in spherical and cylindrical coordinates. Section 5.3: Line integrals and Green's theorem. Section 5.4: Surfaces and parameterizations. Section 5.5: Surface integrals Section 5.6: Derivatives of vector valued functions, div and curl. Section 5.7: Stoke's theorem. Section 5.7: Divergence theorem. Section 5.7: More on Stoke's and Divergence Theorems. Handouts: Differential equations.
 Supplementary handouts: Work and Energy, Angular Momentum, Planetary Motion, Relativity, Center of Mass, Electricity and Magnetism, Euler's Equation, Wave Equations, Heat Equation, Laplace's Equation, Schrodinger's Equation, Dirac's Equation. Various computer assignments. Two "midterm" exams: Wed., Oct. 18 and Wed., Nov. 15, both from 7-9pm and in Science Center Lecture Halls C and D. A final exam scheduled by the University; the preliminary date is Sat., Jan. 13 in the morning.

 BioChem Sections
 Textbooks: "Multivariable Calculus with the Student Solutions Manual" by Ostebee and Zorn "Fundamentals of Biostatistcs" by Rosner.

 Section 1.1: 3-d space and surface. Section 1.2: Parametric curves. Section 1.3-1.4: Vectors, vector valued functions. Section 1.5: Derivatives, anti-derivatives and motion. Sections 1.6-1.7: Dot product, lines and planes Sections 1.7-1.8: Lines, planes and cross product. Appendix C: Introduction to matrices. Sections 2.1 and 1.1: Functions of several variables. Sections 2.2-2.3: Partial derivatives, contours and linear approximations. Sections 2.3-2.4: Linear approximations and the gradient. Sections 2.5-2.6: Theory of derivatives, high order derivatives and quadratic approx. Section 2.7: Max-min, critical points and extreme points. Sections 2.7 and 4.4: More on extreme points, constrained optimization. Section 4.4: Constrained opimization. Section 2.8: Multivariable chain rule. Section 3.1: Multiple integrals. Section 3.2: Calculating integrals by iteration. Section 3.3: Integrals in polar coordinates. Section 3.4: Integrals in spherical and cylindrical coordinates. Rosner Chapter 2: Descriptive statistics. Rosner Chapter 3: Beginning probability including addition laws, multiplication laws, conditional probability, total probability, Bayes' theorem. Rosner Chapter 4: Discrete probability distributions including binomial distributions, Poisson distributions. Rosner Chapter 5: Continuous probability including density functions, mean and variance, normal distributions, approximation by normal distributions. Handouts: Differential equations.
 Various computer assignments. Two "midterm" exams: Wed., Oct. 18 and Wed., Nov. 15, both are from 7-9pm and in Science Center Lecture Halls C and D. A final exam scheduled by the University; the preliminary date is Sat., Jan. 13 in the morning.

 Last update, 9/8/2000, math21a@fas.harvard.edu