Tuesday, February 7, 2023

Lesson 5.2.3: Geometric Sequences -- Investing (Day 106)

e SONG

Chorus:
e (2.718)
Ah, number number (281828)
You are my natural log,
And you got me calculating.

e (2.718)
Ah, number number (281828)
You are my derivative,
And you got me calculating.

First Verse:
I just can't believe the loveliness of graphing you.
I can't believe you're more than two.
I just can't believe the loveliness of graphing you.
I can't believe you're more than two. (to Chorus)

Second Verse:
I just can't believe your digits go forever now.
As long as a number can be.
I just can't believe your digits go forever now.
As long as you're the number e. (to Bridge)

Bridge:
Put a little cash in the bank, money.
Put a little cash in the bank, baby.
I'll make more next year, yeah, yeah, yeah!
Put a little cash in the bank.

100% interest on my money.
Compound it continuously, baby.
I'm gonna take the limit now, yeah, yeah, yeah!
My cash is multiplied by you, e. (to Chorus)

Today is e Day -- named for the constant e = 2.71828, since February 7th is 2/7. So of course I have to perform "e Song" -- a parody of "Sugar Sugar" by The Archies, and inspired by Elizabeth Landau, aka Bizzie Lizzie. It includes as much of Landau's song as I can remember -- I wish that she would repost her parody in its entirety so that I can perform it in my classroom. As it stands, this version of the song is close enough to what Bizzie Lizzie wrote on her blog over 25 years ago.

Since the constant e is much more relevant to Math III than to Math I, this post will mainly deal with the higher math course. Even so, as I mentioned during break (knowing that e Day was around the corner), the Math III students don't really learn about e until Chapter 10 of the CPM text. This is despite logarithms being mentioned in both Chapters 5 and 7.

And I knew all along that the Chapter 7 Paper Test was scheduled for yesterday, so my fifth period class spends most of e Day on test corrections. At least some of the problems that they're working on involve compound interest (though not continuous compound interest or the number e).

I sing today's song in transition from the test corrections to the first lesson of Chapter 8. It's my first e Day performance in three years (when I sang this song when subbing for Chemistry students who were likely to have seen the constant in their math classes). And of course, I play it on my guitar in the key of E major (despite The Archies singing the original in D).

Chapter 8 of the CPM text is on polynomials. The first lesson is on vocabulary -- all those words like degree (and the closely related constant, linear, quadratic, and so on up to quintic), roots of polynomial, and so on. The Math III leader held a meeting yesterday, and he showed us all of the Chapter 8 lessons that he's already set up in DeltaMath -- even one for today's vocab lesson.

It may be e Day, but I'm already looking ahead to Pi Day. The Chapter 8 Test will be scheduled for the days surrounding Pi Day. The one thing about Pi Day is that it's on a Tuesday, but the previous day is a workday for teachers only, not students. And that Monday off will strongly affect the scheduling of the Chapter 8 Test. (Last year there was no teacher day in March -- instead, there was a four-day weekend for Veterans Day as the holiday fell on a Thursday.)

Had March 13th been a student day, it would have been the day of the Chapter 8 Paper Test, after the DeltaMath part the previous Friday (like the Friday-Monday scheduling of the Chapter 7 Tests). But it was decided to be too awkward to have separate Parts 1 and 2 of the test by a three-day weekend during which many students might not be thinking about math (and even worse for classes that don't meet on Tuesdays, like my first period class).

So instead, the Paper Test will be scheduled for Thursday the 16th. On Pi Day itself, there will be some sort of SBAC Prep (and the Paper Test might even contain an SBAC-like question). For me, at least this decision steers a test away from the biggest math party day of the year.

Once again, even though "e Song" is a Math III song, it's somewhat relevant to Math I as well. Today in Math I, we reach applications of geometric sequences, including compound interest. I point out to the students that both today's song and "Compound Interest Rap" are somewhat related to today's topic, even though today's question is much simpler (compounded annually, not continuously).

In second period, I spend a bit too much time on the compound interest question that it takes time away from quiz corrections (which I want to do today, a block day, rather than mess up a Monday lesson). So in fourth period, I only briefly discuss the compound interest problem.

Today is the third day of the week on the Eleven Calendar. (In past posts I've referred to this day as "Sunday," to emphasize that it can serve as a replacement Christian Sabbath.)

Resolution #3: We remember math like riding a bicycle.

There's a Hero Quiz coming up at the end of this week in Math I. Students will have to do calculate without a calculator in order to pass it.

The biggest thing going on today is e Day. But here in Southern California, many NBA fans are also celebrating LeBron James breaking the career scoring record set by Kareem Abdul-Jabbar almost forty years ago. (The time stamp of this post is set to the time the record is set, so that I can acknowledge it in today's post.)

But for mathematicians, that's not nearly as important as e Day.

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