### I feel so unclean

O, the moral depths that a woman will plunder when she’s desperate for money (*): this morning’s tutoring session covered the topic of How to Use Your Fucking Graphing Calculator to Find the Roots of a Goddamned Quadratic, For Crying Out Loud. And I *taught* it. Without snark, flailing of arms, or even a modicum of political commentary. And, so help me God, I even acted - convincingly, I think - as if I *enjoyed* it. I take some measure of comfort in the knowledge that my tutee will probably forget this lesson, along with all others, the minute he finishes writing his provincials (if not before), but still. They don’t make soap strong enough.

You won’t think less of me for this, will you?

(*) Not the case here; my savings will cover groceries and rent. Today’s spoils will finance a meal or two of Dim Sum at the Buddhist restaurant, which I think lies somewhere between Love and Esteem on Maslow’s Hierarchy of Needs. I guess this makes me even more of a skank.

Does dim sum at a Buddhist restaurant imply vegetarian dim sum? If so, do tell. (I’ll be in Vancouver sometime…)

Well, in truth, I

dothink less of you now; but only a little less: I would still marry you, if given the chance.*giggles*Did you at least discuss the significance of the discriminant? Did you describe how to avoid losing significant figures by not subtracting two nearly equal numbers? did you at least make your student work for the TI dog and pony show?

Kirsten, it does indeed, and it is the food of the gods. I’ll email you the details.

Eric, I did, see, in the

previoussection, the How To Find The Roots Of A Quadratic By Mathematically Legitimate Means chapter. But the next section was all about the TI, and presented the graphing calculator method as being just as good a way to find the roots as all that crap with the factoring and crap, and who can blame a student for wanting to do less instead of more? I weep.Hi Kirsten,

My favourite vegan (I think) buddhist restaurant in Vancouver is Bo Kong’s on Main St, just a few blocks South of Broadway. I definitely recommend checking it out if you are in town for a few days!

My favourite is the crazy all-you-can-eat place in Richmond. I went there with Innie when I helped her move out of Vancouver. The feeling of pulling up at a buffet in a U-Haul… priceless.

MS: would you be so kind as to email me your phone number, or is it still the old cell..

What really does amaze me is that a student who doesn’t learn [simple fact here] can instead remember that you press MATH, INS, CALC, MODE, GRAPH, SOLVE, … , ROOT, ENTER (yes, that was a nonsense string of commands, but to me ALL of them are) to do whatever.

I don’t get it - factoring a quadratic is usually so much easier than squinting into the dang LCD, mashing some buttons, wondering how you got roots of roots of 4.989 and -87,000,000, chewing your pencil, realizing you pushed the wrong button, then starting over.

Heck, this is one of the few places where they can skate by by just memorizing the quadratic equation without having the foggiest idea how it works.

I missed it — did you get your computer fixed?

RH, it really is quite something, no? But these are the kids who grew up in the post-Nintendo era, so perhaps their Mad Calculator Skillz are a natural extension of their video-game-playing skills? Not that I am terribly proficient in either, mind you.

IG - quadratic formula is easier than using the bloody TI, but factoring is harder if you’ve never learned your times tables. (I spent much of one session this week showing my student how he could find two integers whose product was 11 and whose sum was 24. The only divisors of 24 that he knew offhand were (1,24) and (2,12) and he couldn’t think of any way to come up with the others. “Well, you know that 1 and 2 are divisors - maybe you can try 3?” I suggested. “How do I do that?” he asked.)

Meep - nope, STILL in the shop. Apparently it was in really bad shape (though I think that my data is safe), and needed the computer equivalent of a heart-lung transplant. One of the needed parts just got in today, and when that gets installed, it should be on its way back to me, this time for real. Argh.

And lobster - ah, I’d blush if I were the blushing type, but let me tell you, I may be cute on print, but imagine this full-time. I’m insufferable in the flesh, I am.

Okay–you’re being forced to use calculators. At least it’s relevant to the calculator user that to solve $x^{2} - 100x +1 = 0$ the expression $\frac{100 - \sqrt{9996}}{2}$ is not as good as $\frac{2}{100 + \frac{9996}}$.

For a 1950s look at that and similar issues, look at Usually Work, by Forman Acton.

Oops–that was supposed to be Numerical Methods That Usually Work, by Forman Acton.

Graphing calculators are wonderful, for people who don’t need them.

If a person understands the idea of “roots of a function” then the graphing calculator is a neat way to play around with the function to see how the roots change. If a student doesn’t understand how to find the roots of a quadratic by factoring or completing the square then knowing how to find approximate roots with a calculator is the very definition of Useless Knowledge.

I agree with richard. It is quite boring to solve 10 quadratic equations by hand once the student understands what it is they are actually doing, so a calculator in that case is a good thing. But the idea is not to teach students how to understand; the idea is to teach them how to follow instructions, because in the near future their jobs will involve a lot of mechanical routine stuff and almost no thinking. So the textbooks cater to that kind of training. Then again what do I know.

Couldn’t the student just have factored or used the quadratic formula?

Last year I got to know someone who is a returning student, and a victim of this “calculator emphasis” math.

She couldn’t even do algebra properly; the manipulation of symbols was beyond what she had been taught, which was to plug in numbers and go straight to arithmetic. Derive the quadratic formula? Beyond her, and probably always will be; not that’s she’s dumb, she’s been systematically mis-educated.

That’s sad.

Amy, yes, exactly, which is why this exercise is so inane. The whole curriculum is full of this stuff: “Here’s a relatively simple concept. Now, instead of giving you the tools to actually understand it, we’ll subject it to your $150 calculator.”

Engineer-Poet - I can count on the fingers of one hand the college students I’ve taught who even know what the term “derive” means in that context. It’s not just that they can’t, say, derive the QF on their own; it’s that it wouldn’t even occur to them that that’s something that could be done. In their view, the QF was divined by some Genius Mathematician who happened to know all of the magical rules of mathematics that are all well beyond the grasp of the common people.

I swear we all had to derive the QF in grade 10.

I know a girl’s gotta eat and all, especially if it’s dim sum. But if you EVER send this student on to my calculus class at Utah State University, I will eat him for breakfast, because I make a point of writing exams that make your graphing calculator a useless heap of plastic. If he can’t solve quadratic equations in exact form and he’s in my class, he’s not only toast, he’s toast with frickin’ blueberry jam on top.

Hell, if I sent this kid to any of the college classes - including the supposedly-this-is-equivalent-to-a-grade-12-math-class classes - he’d be toast. Fortunately, this kid won’t be taking your calculus class, or mine, or anyone else’s; he just needs this particular graphing calculator how-to class for a vocational program. I’m familiar with the math component of that vocational program - no numeracy skills beyond plugging numbers into a calculator are required. So, I can rationalize my actions (that is, showing him what he needs to know to get through the tests, rather than, say, teaching him mathematics) this way.

Also: today’s dim sum was especially tasty.