this is not a journal title

I think in other posts I've stated my support of time-money as the driving unit of value.

So your commute costs you:
t(v) = 20 * Distance / v
g(v) = Av + Bv^2

and we want to minimize t(v) + g(v). Fun. :)

Do you have any fuel efficiency stats for your car so we can solve for constants A and B?

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Sorry, fuel efficiency g(v)= Av + Bv^2 + Cv^3

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oh, wait , +D.

http://auto.howstuffworks.com/question477.htm

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That formula is for POWER, not fuel efficiency. We need a quadratic (or at least an even power function) b/c we need an absolute maximum. A cubic equation implies that as you drive infinitely faster, you can get infinite fuel efficiency.

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Yeap, I was thinking about exactly that as I drove in this morning. The stats I have are rough. What I'm willing to use are that at 74 mph I get 36 mpg, and at 55 mph I get 40 mpg, and 55 mph gives the absolute maximum. I'm going to check with

jethereal later, I'm pretty sure that's sufficient information to solve for those constants. Though actually it'd be more standard to write g(v) as follows

g(v)=Av^2+Bv+C

Don't ever forget the +C. ;) And also, I'd rather express it all in minutes so I don't have to deal with decimal hours, but that's a trival conversion. But what's less slightly less trival is that the total time should have a +20min b/c regardless of how fast I drive on the highway I still have local streets and traffic at the end. I should have something whipped up by the end of the day.

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In response to your icon, the math department at neu had this fun solution:

1/n * sin x = 1/n * sinx = 1 * six = 1 * 6 = 6!

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best-ken-ever.livejournal.com

But,

gemini6ice, how can 6 = 6! possibly be true?!?! The only integral solutions to x=x! are {1,2} Surely, you must've made a mistake in your calculations (;

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i remember when we encountered factorial in my pre-calc class back in HS, and one kid had never seen it before. When he read the problem aloud, he just shouted the part that was in factorial. ^o^

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best-ken-ever.livejournal.com

::actually laughed out loud at work:: Amazing (:

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Reminds me of one a math teacher told me. He taught them how

Lim(x->0) of (8/x) = ∞

And on an exam he gave

Lim(x->0) of (5/x) =

to which the student replied with a sideways 5.

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jrtom.livejournal.com

*snort*

I have to say that I would also have been tempted to answer that question that way.

On a slightly related note, I just today realized that one can interpret your icon as "no, you idiot, x is over here by the 0 symbolizing the number of points you're about to get". :) (Yes, I know that's not what the red 'x' symbolizes. But it tickles me that you can read it that way.)

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Every time I see it I think x₀ as in "initial x position."

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jrtom.livejournal.com

*nods* I can see that. Although it looks a bit more like X₀, i.e., perhaps the first in a series of state variables X or something, rather than a lower-case x. To me, anyway.

So many silly willful misinterpretations, so little paper on which to write them...

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LOL!!!!!

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Doesn't 0!=0 ?

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best-ken-ever.livejournal.com

0! is defined to equal 1 to satisfy a bunch of other math things. One way to think about it in the real world is, with 3!, you have 3!=6 ways to permutate 3 objects. You have 0!=1 way to permutate "no" objects. It's silly, but that's the way I've always thought about it. My way of permutating no objects is the same way that anyone else can do it. (:

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Oh, you're right. My bad, I forgot. :-P

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always-going.livejournal.com

We're doing imaginary numbers in math. I might need your help when we get our graded assignments....

Topology was sweet, though. And the 4 question assignment only took me two and a half hours!....only 2 of us actually completed the problems! Hooray!

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always-going.livejournal.com

Okay, after reading the rest of the comments posted I feel kind of like a fool.

I would like to add, that in my defense, I haven't studied math in five years.

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Hey kiddo, don't sweat it. Of the four people posting here other than you one's a physics prof (me), one's a physics grad student, one I met through nerd camp, and the last does accounting (also super math heavy). You're the most normal of us all! :-P And if I can infect you with a love of math/science, I will rest happy.

BTW, how's your bird (was his name Jomei?) taking your absence? Gabe grew in one extra flight feather last weekend and OMG she's had *such* a blossoming of personality. ^_^

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didn't know you were a physics prof! that's pretty damn cool :)

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"Assistant Professor of Integrated Science / Physics"

I'm at a community college (aka junior college, aka 2-year school) which means in practice I teach physics, astronomy, earth & space, physical science, and occasional random other things, all at the freshman level, when not lower. :-P One of our mutual friends (I think

the_xtina) told me to read your LJ in one of those memes b/c apparently we have some things in common. I seem to recall you're a math grad, but I could be mistaken.

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Physics semigrad (was doing a PhD in high energy physics, took a terminal MS and got out). If I go back, it'll be in CS, not physics - much as I love the subject I don't think I have a PhD's worth of interest in it. (Then again, I might just have been stupid to go into high energy because Rice didn't have anyone working in the area I was really interested in - should've taken a year and reapplied for a transfer to other schools)

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always-going.livejournal.com

Jomei and mom seem to be doing very well. Often I will get voicemails of "Hello! Hello! How're you!? Shower?"

It is, however, mostly my mom squawking.

I get to see them on the 22nd, though! I'm going home for a couple days :]

It's all right about the math, I'm pretty excited about the class. Next we're doing some Crypto. And then map color theory (I forget the fancy name). Should be excellent :] I think at some point we're going to mess with Latin Squares...it's either that or graph theory!

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That actually sounds like a fun math class. :) Doing little bits of everything interesting, rather than math just for the sake of math. I've done bits of all those, but only got to do them after taking all the hard and boring stuff.

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When is a donut like a coffee mug?

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When you're a topologist! *ba-dum-bum!*

It doesn't get any better than this, folks, but sure, feel free to ask me math questions. :) You can also email me zandperl-AT-gmail-DOT-com if you want.

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