Monthly Archives: September 2009

From whence this came…

UPDATE: Here is my Advice from Algebra 2 Students Past, in full glory.

Today I was compiling and typing up my “advice from Algebra 2 students past” to hand out to my kids this year. And I forgot about a striking passage from one of my students:

It will behoove you to understand going into class what exactly Mr. Shah wants from you, which is an attentive, honest, and interested student. It has taken me six months to realize what Mr. Shah really wants from you; he wants you to ultimately be a good person in the world.

Where that came from, I have no idea. None of my other students wrote anything like it. It rang so sincere and specific in the way it was written that I know it wasn’t just a casual, flippant remark. Of course I glowed when I read it — because the student hit on something even I hadn’t been able to articulate. My primary goal is to get my students to understand and be able to do mathematics, but these kids are in the process of learning how to be adults. And whether my kids remember completing the square years down the road is ultimately less important than the person they forged through trying to learn how to complete the square. Not that I ever say that to them, really.

Which is why I’m  darn curious from whence this remark came from, though. Cuz I have no freakin’ clue.

Imagining the First Day of Calculus

At one point during my first class, I want to drive home a point. You guys know a lot, and I want this course to help it all hang together.

I’m going to ask them to spend a few minutes minutes solving the problem: 2x^2-56x+1=0

Then I’m going to go around and have students explain how they got their answer, why they think they’re answer is the answer, what they know about the question, whatever.

Who wants to bet that 100% of them graph it on their calculators or use the quadratic formula?

I’m counting on it. I will then show them an example of their graphing calculator lying to them (there are a million of ‘em), and then say “why does the quadratic formula work? why are we allowed to use it?”

We’ll then take a moment and say “what do we need to know to solve this problem? I’ll start by throwing something out: we have to know what a variable is.”

So we’ll throw a bunch of things on the board: variable, number, exponent, addition, square roots, etc.

Then I’m going to reveal the big secret to mathematics, the secret that all teachers have kept from them until now: all we’re doing to solve problems is to turn something we don’t know into something we do know.

This is the rant I have playing in my head…

So when we first learned quadratics we didn’t know how to solve ‘em. We had only seen baby linear equations. But guess what? When we learned to solve quadratics two years ago, we turned these horrible grossities (quadratics) into beautiful nice-ities (linear equations). Watch!

2x^2-56x+1=0

2x^2-56x=-1

x^2-28x=-\frac{1}{2}

x^2-28x+196=-\frac{1}{2}+196

(x-14)^2=\frac{391}{2}

(x-14)=\pm \sqrt{\frac{391}{2}}

x-14=\sqrt{\frac{391}{2}} and x-14=-\sqrt{\frac{391}{2}}

I didn’t know how to solve the quadratic, but I do know how to solve (two) linear equations!

This procedure is completing the square. I know y’all remember it — vaguely. I know y’all hated doing it. But why did we evil math teachers foist it upon you? Because what this lengthy, arduous, annoying process did was took something gross, and turned it into something nice. The process wasn’t super nice, I know, but taking a step back and looking at the forest for the trees, it did that magic little math secret: turned what you didn’t know how to solve into something you did.

And look at all you needed to know about in order to make this happen. Numbers, addition, exponents, square roots, positive and negative, linear equations, variables. In that one equation

2x^2-56x+1=0

is a whole universe of knowledge! And you KNOW that knowledge. And in this class, we’re going to time and time again see equations that we might not think we know how to solve. They’ll look scary and unfamiliar like

\int_{-3}^{3} \sqrt{9-x^2}dx

But we’ll turn it into something we are more familiar with. Just don’t lose the forest for the trees. Don’t get stuck in the muck and mire of the procedure and not forget about why we’re embarking on that particular path, or what ground the path is built upon.

Our mantra: take what we don’t know and turn it into what we do. Math is an art. The creative aspect of it is finding the right path to turn what we don’t know into what we do know. Therein lies the puzzle, the beauty, and yes, the frustration.

PS. This post is basically a recap of this previous post. I just think it will be fun to talk about on the first day.

A Vacation From My Vacation, or a Toast to High School Friends

I need a vacation from my vacation within a vacation. (Translated: I need a week to recover from going to a high school friend’s wedding at the very tail end of my summer vacation.)

I just got back from Seattle, spending 5 days with high school friends, going to a wedding. What struck me is that we’ve known each other for over 13 years, and that these particular friends have actually grown closer to me with each passing year instead of more distant. High school can be extraordinarily important, socially. Heck, when I moved from my first high school (few friends) to my second high school (lots more friends), I felt free to be whoever I was, without the weight of years and hardened opinions of classmates weighing me down. I was able to become who I became — a colorful, irreverent, independent, overly dramatic personality — in high school.

Even though I very rarely commit anything about my personal life to this here blog, I just wanted to give a visual toast to those friends who forged the backbone of who I am today in that crucible that was high school.

(And I just know all y’all were dying to know what I look like. Hot, right?)

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