Comments for 360

Comment on Kid Snippets Math Class by Sherry Lewis

Sherry Lewis — Tue, 07 May 2013 17:42:45 +0000

Outstanding! I guffawed my head off!
Lambchop

Comment on Kid Snippets Math Class by Ξ

Sat, 04 May 2013 23:25:38 +0000

I showed them in my classes too – I love the Cooking Show one also. And yes, the accuracy at times makes it especially funny.

Comment on Kid Snippets Math Class by Emily H.

Emily H. — Fri, 03 May 2013 15:38:23 +0000

I love these videos, and my students love them, too. They are perfect to show on a day with a disrupted schedule before a break because they are short, funny, and 100% school appropriate. I’m glad you’re spreading the word! The “Math Class” scenario is alarming similar to what it feels like to teach/be a student in real life, but I think that makes it even more funny.

Comment on Third Derivatives in the News (Again) by absurdenough

absurdenough — Fri, 05 Apr 2013 12:19:23 +0000

Hmmm ….

The folks here have some examples too – http://boards.straightdope.com/sdmb/archive/index.php/t-572473.html

I think the reason could be something like this … at least as far as interpreting experimental data is concerned.

Let’s say there is a 12th power dependence of a physical parameter y on another parameter x =>
y = k.x^12

and the region of interest is x = 1 … 10

y’s rise with increasing x would be too steep to keep track of with adequate dynamic range. We would either see saturation/out-of-range errors with slightly high y’s or if our system is geared for measuring high values, we would not have the ability to measure the lower end values with adequate resolution. Classic range vs sensitivity challenge.

In such a situation, detecting a 12th order dependence would be a very difficult measurement/analysis problem.

Comment on Third Derivatives in the News (Again) by adamas

adamas — Fri, 05 Apr 2013 11:42:02 +0000

the van der waals force has an inverse 6th power.

Comment on Third Derivatives in the News (Again) by absurdenough

absurdenough — Fri, 05 Apr 2013 05:06:23 +0000

It’s interesting how high order derivatives appear with lesser frequency than lower order ones … whether in economics or physics. Same with exponents. We don’t see too many y = k. x^12 expressions, for example.

Is it something fundamental to nature or is it because such a relationship would be very hard to come up with based on experiments?

Comment on 25+ Ways to Multiply by Nash

Nash — Thu, 04 Apr 2013 03:24:39 +0000

I am trying to find the name and book of a Naval architect who was throw in concentration camp in WW 2 who devised and later on wrote the book on alternate method of calculations the technique could beat a calculator. Can someone help.

Comment on Third Derivatives in the News (Again) by Ξ

Thu, 04 Apr 2013 00:58:48 +0000

I think I see what you’re saying, although I feel two ways about it: I can see both “dollars” and “dollars per year” as being appropriate ways to talk about the deficit. [A deficit of $1 Trillion each year for 3 years would be $3 Trillion, and I can see that as 3*$1 Trillion or as (3 years)*($1 Trillion/year).]

But I do agree that wherever the detail of it not matching occurs, it isn’t a perfect analogy.

Comment on Third Derivatives in the News (Again) by absurdenough

absurdenough — Tue, 02 Apr 2013 11:34:58 +0000

I see what you mean, but the continuum versus discreteness distinction fails to capture the real issue here.

Let us take the conventionally continuous example of water flowing through a pipe at a rate of 1 liter per second.

The analogy would then be :

Deficit = Net volume of water that has flowed in a year = 31536000 liters
Debt = Net volume of water that has flowed till date
Rate of debt = Flow rate of water = 1 liter per second = 31536000 liters per year

Even if fiscal transactions were perfectly continuous like flowing liquids, the distinction between a rate and a short term aggregate would remain. The limits of integration in the deficit and debt case would be different but they would still be dimensionally same. No d/dt.

Sorry if I’m being pedantic here.

Comment on Third Derivatives in the News (Again) by Ξ

Tue, 02 Apr 2013 11:00:39 +0000

I agree that with deficit (and walking), it’s more natural to do it in discrete quantities, whereas derivatives are continuous, so that makes for some awkwardness and an imperfect analogy. I don’t think of the units as actually being incorrect, but I think the problem might be average vs. instantaneous.

In your daily walk, I *do* think the units can reasonably be km/day [you walk 1 km/day], but that’s more of an average daily speed than an instantaneous one, which I think is the reason it doesn’t quite sit right. The same with deficit and: I think that deficit, while measured in dollars, is an annual measurement so the units are reasonably dollars per year (because it’s how many dollars are added in a year), but because it’s done in 1-year chunks, it doesn’t have the instantaneous aspect that a derivative ought to have.