David Berlinski’s A Tour Of The Calculus – From Points to Integrals!

Calculus

I have taught calculus for decades, but David Berlinski’s book, A Tour of the Calculus, made me look at the subject in entirely new and entertaining ways. He starts at the beginning: points and lines, and slowly builds up the mathematical foundation upon which calculus rests. Along the way, Berlinski shares his wonder and love of mathematics. Concepts I have taken for granted for years suddenly appeared to me in a new light.

Berlinski’s sometimes florid style could be off-putting to some readers, but I found it kind of charming:

If the calculus comes to vibrant life in celestial mechanics, as it surely does, then this is evidence that the stars in the sheltering sky have a secret mathematical identity, an aspect of themselves that like some tremulous night flower they reveal only when the mathematician whispers. It is in the world of things and places, times and troubles and dense turbid processes, that mathematics is not so much applied as illustrated.

So, I enjoyed his over-the-top delight in unfolding the miracle of the calculus to his audience. He also has a wicked sense of humor – throughout the book, his tongue is firmly in cheek:

Students who need not be persuaded that gender studies are good for something often ask innocently whether analytic geometry is good for anything.

He gives the most original explanation of what a function is that I’ve ever seen:

A function, those thousand bright and brittle textbooks say, is a rule that assigns to each element in a set A a unique element in a set B. On the left are the elements in A, on the right, the elements in B. The function acts to pick one in A and assign it uniquely to one in B. This definition is current in the mathematicians’ lounge, where the mathematicians gather after class, and where it is always four on a gray Friday afternoon, the rain just beginning to streak the sooty windows. The image of a function thus evoked suggests one of those ghastly preadolescent dances in which sullen boys are lined up along one side of the ineffaceably smelly gymnasium and preening girls along the other, an energetic social science teacher seizing one of the hideously embarrassed boys and, after dragging him by the lapels of his stiff sports jacket, depositing him in front of a pleased but stout and red-faced young girl: Gregory, you dance with Jessica here. The homely tableau succeeds in spite of itself. The sets A and B are represented by boys on the one hand, girls on the other, and the function itself by the Czar’s dancing mistress, mysteriously transposed to suburban Teaneck, New Jersey, and acting energetically to pick a boy and assign him to a girl.

High school textbooks aren’t spared his wit:

The examples offered by elementary algebra are often uninspiring if only because no one wishes really to know which numbers correspond to the unknowns, the unknowns in word problems referring always to a strangely meditative farmer standing forlornly on that illustrated textbook hill of his, wondering in a way that suggests nothing of the power of mathematics how many turnips he might grow if he had two tons of fertilizer.

Along the way, we sit in on some of his classes as he tries to get his bored and confused students to share his enthusiasm for the Intermediate Value Theorem, among other topics. Berlinski really shines when he provides beautiful little portraits of the mathematicians who discovered and developed the math behind the calculus: Newton, Leibnitz, Cauchy, Euler, Dedekind, Lagrange, Riemann. I gained a new appreciation for the difficulties the concept of a limit presented to rigorous mathematicians. I especially enjoyed Berlinski’s tribute to Reimann, who died tragically young:

He was in his temperament a geometer, in his affiliations a Platonist, in his soul a visionary; he saw through appearances to a world less voluptuous and less complex than the real world, but more ordered, harmonious, stable, and beautiful. … Alone among the mathematicians of the nineteenth century, he saw what he needed to see before ever he acquired the symbolic apparatus with which to express his vision; his certainty about each of his discoveries was richly merited, but exotic and spooky.

Even if you didn’t like math as a student, you will be entertained by Berlinski’s presentation of it here. He doesn’t assume the reader knows anything, and he carefully explains every new concept that he introduces. There are excellent illustrations throughout, clear and easy to understand. By the end of the book, you will have a firm grasp of both differentiation and integration, and the Fundamental Theorem of Calculus that weds them.

I’ve read many books on math that are written for the layperson, and Berlinski is definitely one of the most approachable. He joins Ian Stewart and Steven Strogatz as writers who never talk down to their audience, but manage to kindle interest in a subject that too often strikes fear into people’s hearts. Take Berlinski’s Tour of The Calculus, and see why

The calculus is the story this world first told itself as it became the modern world.

2013 Winterim: Light, Math & Color

I taught another three-week stained-glass mini-course this year. After my students learn the basic technique of copper-foil stained glass windows, they research a math topic, write a paper on it, and illustrate it with a window of their own design. Topics this year included systems of inequalities, the Fibonacci Sequence, corresponding angles formed by two lines and a transversal, the Four-Color Theorem, and the Pythagorean Theorem among others.

Here’s a gallery of their finished windows:

Strange Attractors

This post isn’t about the strange attractors you hear of in chaos theory; rather, it’s about an excellent poetry anthology edited by Sarah Glaz and Joanne Growney. I’ve linked to Joanne’s blog, Intersections, before. After showing it to my school’s librarian, she ordered a copy of Strange Attractors, and it arrived a few days ago.

I haven’t had chance to really delve into it, but it looks wonderful. Glaz and Growney have selected poems from the beginning of recorded history up to the present. What holds it all together is their subject matter: love. Yes, mathematicians are susceptible to it, and these poems are ample illustration of the many ways math and poetry complement each other in expressing that emotion.

Most of the poets use plain words to get their point across, but there are several clever exceptions. I especially like this one by Kaz Maslanka, entitled “Sacrifice and Bliss”:

 

 

It reminds me of a Tolstoy quote I have in my classroom: “A man is like a fraction whose numerator is what he is, and whose denominator is what he thinks of himself. The larger the denominator, the smaller the fraction.”

Anyway, even if you’ve forgotten most of the math you learned in high school, you’ll find plenty of wonderful poetry to enjoy in this anthology. If you love math, you’ll derive (!) even more pleasure from it. If you teach math, Strange Attractors will be an invaluable resource for you and your students.

A Really Useful Online Graphing Calculator

The good people at Desmos have made an excellent online graphing calculator even better. It’s incredibly fast and versatile. For example, if you input y = m*x + b, it will automatically ask you if you want to create sliders for “m” and “b”. Here’s an example of a quadratic function with sliders:

It will plot implicit relations:

As well as inequalities:

There’s even a “Share” button that lets you post your creation to Facebook, Twitter, or Google+. Once you create an account, you can save your graphs online, to be used later. There are countless applications of this product in the math classroom.

Click here to try it out!

Download a brief User’s Guide here.