Monday, December 15, 2008

Defending the Family (Mathematical) Honor

I have now done my part to uphold the family honor: I have finished the diff equations class and barring some bizarre problem like this has all been a dream, I should have an A. Hopefully this effort, combined with my sister's previous ones, will help counter the blemish of my dad's differential equations F.

I am now well-prepared to begin forgetting more about differential equations than most people will ever know.

...which, by the way, has to be one of the least compelling arguments for credibility ever. "I have forgotten more about macroeconomics than you will ever know!" or "She has forgotten more about state purchasing guidelines than he ever knew!" This is particularly strange when used as a reason that the speaker should be trusted to make a decision, etc., over the other person mentioned. Wait, we're supposed to put all this confidence in you because you used to know something about the topic? I'm going to put my trust in someone who has learned a lot about something and not, you know, forgotten it. I used to think that this phrase was merely a joke, but it seems that people do use it seriously as a testament to an individual's knowledge and expertise (and not, as it may sound to one upon first hearing it, their cognitive decline).

Do the math. Hey, we can do this in the form of a GRE quantitative comparison question.

"Ann has forgotten more about math than Brenda ever knew.

Column A: the amount Ann currently knows about math
Column B: the amount Brenda currently knows about math

A - the quantity in Column A is larger
B - the quantity in Column B is larger
C - the two quantities are equal
D - the relationship cannot be determined from the information given"

Ann forgot X amount, and once knew Y amount, and currently knows Y - X amount about math.

Brenda forgot S amount, and once knew T amount, and currently knows T - S amount about math.

X > T

Is Y - X larger, smaller, or equal to T - S?

It's easy to see if you try different numbers. Say X = 10 and T = 5. How does Y - 10 compare to 5 - S? That depends on Y (how much Ann once knew) and S (how much Brenda forgot).

If Y = 100 and S = 1, then 100 -10 = 90 > 5 - 1 = 4.
If Y = 11 and S = 3, then 11 - 10 = 1 < 5 - 3 = 2.
If Y = 14 and S = 2, then 13 - 10 = 3 = 5 - 2 = 3.

So without additional information, the statement means squat in terms of who knows more about math right now.

3 comments:

rvman said...

I know more about Economics than most people have forgotten!

Tam said...

Wow, rvman. That is very true.

Jen M. said...

One thing is, though, that even if you've forgotten details, it (having studied math etc) changes the way you think about problems, and you can also be pretty confident that you'll be able to pick it back up more quickly than someone never exposed to the concepts... not that I would use "I've forgotten" as a legitimizing tactic but there is still some truth to it.