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Mathematics Goes to the Movies

by Burkard Polster and Marty Ross

**Mean Girls (2004)**

2:07

Quite a bit of the action in this movie takes place in a math classroom. There
are various mathematical bits and pieces that can be spotted in this classroom.

Model of five tetrahedra combining into an icosahedron. Frame of a cube. Rubics
cube. Both Hoberman spheres. Math art, pentagram, Trigonometric equation poster,

Ambigrams: Amateur ambigram. Various ambigrams by Scott Kim Teach/Learn, Level,
False/true, Mirror, upside/down.

Important rules above blackboard:

e^x =y x=ln y

upside/down

Pythagoras?

d/dx e^x =e^x

d/dx ln u= 1/u du/dx

d/dx ln x=1/x

Good calculus blackboards

(exp z)(exp w) = exp (z+w) -> corresponding power series’

5:24

Mathart etc.

00:06:18

You're taking 12th-grade calculus?

- Yeah, I like math.

- Why?

Because it's the same in every country.

That's beautiful. This girl is deep.

8:07

Matheletes good blackboard12:15

blackboard

00:12:43

By eighth period, I was so happy to get to math class. I mean, I'm good at math.
I understand math. Nothing in math class could mess me up.

Gets messed up and recovers when teacher asks a question.

Cady: A_n=(n+1)/4

Teacher: That’s right.

Blackboard

13:45

Good calculation about calories. Cady does it in her head. 00:15:39

I'm Kevin Gnapoor, captain of the North Shore Mathletes.

We participate in math challenges against other high schools in the state, and
we can get twice as much funding

if we've got a girl. So you should think about joining.

15:55

Caty: I think I am joining the mathletes.

Virginia: No, no, no you cannot do that. It’s social suicide. Damn you
are so lucky to have us to guide you. 21:21

Teacher: Cady, I do hope you join Mathletes, cause we start in a couple of weeks
and I’d love to have a girl on the team just you know the team could meet
a girl.

Cady: I think, I’m gonna do it.

Teacher: Great!

…

Damien: You can’t join Mathletes, it’s social suicide.

Teacher: Thanks Damien.

22:53

(And with Virginia’s blessing I started talking to Aron more and more.
On October 3rd he asked me what day it was. )

Cady: It’s October 3rd.

Two weeks later we spoke again.

Aron: It’s raining.

Cady: Yeah.

(But I wanted things to move faster, so I followed my instincts)

Cady: Hey, I am totally lost. Can you help me. (but I was not lost. I knew exactly
what Miss New??? Was talking about.)

It’s a factorial. So, you multiply each one by n (wrong)

Is that the summation?

Yeah, they are the same thing. (wrong. It was all wrong)

Cady: I get it now.

00:45:32

So, what did you get for this one?

Well, the first time I did it, I got a zero.

- Wrong.

- But then when I checked it, I got one.

- There you go.

I got one too.

Yeah, you have to check it because sometimes the product

of two negative integers is a positive number. Yeah, like negative four and
negative six.

01:22:42

Welcome to the Illinois High School Mathletes State Championship. Let's start
the competition. Here is the first question.

Twice the larger of two numbers is three more than five times the smaller, and
the sum of four times the larger and three times the smaller is 71. What are...?

- North Shore?

- Fourteen and five.

1493

That is correct. Question number two. Find an odd three-digit number whose digits
add up to 12. The digits are all different, and the difference between the first
two digits equals the difference between...

- Marymount?

- 741.

- Correct.

01:24:51

Contestants, find the limit of this equation.

Calling somebody else fat won't make you any skinnier. Calling someone stupid
doesn't make you any smarter. And ruining Regina George's life definitely didn't
make me any happier. All you can do in life is try to solve the problem in front
of you.

- The limit is negative one.

- Oh, crap. I lost.

That answer is incorrect.

Now, we are in a sudden death. If Miss Heron can answer this problem correctly,
we have a winner.

Limits. Why couldn't I remember anything about limits? Limits. That was the
week Aaron got his hair cut.

(fades to)

Oh, God, he looked so cute. OK, focus, Cady. What was on the board behind Aaron's
head? If the limit never approaches anything... The limit does not exist.

The limit does not exist!

Our new state champions,

- the North Shore Mathletes.

- Yeah!