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#226 Dark Discussions at Cafe Infinity » Speed Reading » 2005-12-07 19:10:13

ryos
Replies: 8

Question: Why isn't this standard curriculum in schools? Do you know of a school system that teaches speed reading to everyone?

I ask because it's such an incredibly powerful tool, and I still have yet to develop it because other things (like school) keep getting in the way.

Speed reading is not based on intelligence; it's purely a function of visual processing, so everyone (except those with visual processing disorders, like a cousin of mine) can learn it.

Another thing: physical education is a joke. PE classes should teach us about our bodies: correct posture, "maintenance" stretches and the like. I wish high schools offered a massage and chiropractic electives. I'm willing to bet that this is not a difficult body of knowledge to grasp; we shouldn't be beholden to professionals for thinks like basic chiropractic adjustment when family and friends could potentially do the same for each other.

What do you think?

#227 Re: This is Cool » Philosophy of math » 2005-12-07 19:00:32

Chaotic Neutral wrote:

Why isn't logic a science?

My dictionary defines science as "The intellectual and practical activity encompassing the systematic study of the structure and behavior of the physical and natural world through observation and experiment" (emphasis mine).

Science involves logic, but logic is not science.

Rod wrote:

So a cheap calculator can do something hopelessly beyond us. But the most advanced computer couldn't survive on a camping trip (without help!).

Or another example, something we do constantly: image recognition. This is very, very hard to get a computer to do reliably, and is one of the things holding robotics back.

Our brains are broken in odd ways. We have a brain that stores every input it ever receives, and then promptly forgets where. Its autonomous function processing is incredibly powerful--when we train it to do things, it can do a large number of them at the same time. One example is sight-reading music. But, our higher function processing is annoyingly modal (to use a computer nerd term) - that is, only one task fits in there at a time.

I don't know how they came up with the oft-quoted figure that humans only use 10% of their brains, but it feels true to me.

#228 Re: Maths Is Fun - Suggestions and Comments » Minesweeper MathsIsFun Style » 2005-12-07 18:41:36

More bugs!

1) I once had a shovel disappear to no avail (I think I may have dropped it between squares), but I haven't gotten this one to repeat.

2) You can flag a square that has been marked clear. Doing so doesn't seem to have any effect on winning (you still win, even if all your clears are marked).

3) I ran out of flags, and it wouldn't let me win. The board below is completely solved (I think), but I hadn't the flags to mark them all.

#229 Re: Jai Ganesh's Puzzles » Problems and Solutions » 2005-12-07 16:48:44

The only thing I can think of is that I didn't get the biggest possible triangle. My thinking is that the largest equilateral triangle will have all three vertices touch the circle, but I can't prove that to be the case.

I'll wait for irspow to post his solution and see where I went wrong.

#230 Re: Jai Ganesh's Puzzles » Problems and Solutions » 2005-12-07 15:49:54

I fixed mine (I think).

irspow: Here's an example of the hide tag:

[ hide=Hide Tag Example ]Examples are nifty.[/hide]

Here's what that code does:

Just leave out the extra spaces I put inside the opening hide tag--I did that so the forum wouldn't convert it into a button. smile

Note that the text following "hide=" is placed in the button.

#231 Re: This is Cool » Solar Zinc » 2005-12-07 07:06:48

I had it wrong (the second part, I mean). I had thought that bocado was feminine (bocada), even though it made no sense in the context of the saying I thought I had heard (so I wrote it as india rather than indio). I actually had to research it! yikes

"Indio" in colloquial Nicaraguan means a person that is base, crude, and rude; it's an insult. Nevertheless, the saying is not insulting. (Go figure. Languages are strange.)

The general meaning is, "I've eaten, so I'm leaving," and "I'm still here, so I must still be hungry!"

#233 Re: This is Cool » Solar Zinc » 2005-12-06 04:10:24

Sounds cool! Hook the panels into the lines, and throttle down the plant.

The trouble is (as has always been the case with PV) that that much photovoltaics would be prohibitively expensive. I wonder if it would be more cost-effective to put wind turbines under the lines?

#235 Re: Dark Discussions at Cafe Infinity » Firefox 1.5 Released » 2005-12-05 11:03:32

It's also standards-compliant, which means nothing to most people but a great deal to web developers whose web sites work on everything BUT IE and we then must go through a horrible process of hacks to try and make it work because 80% of the web-using public uses it.

If the web devs didn't code around it, most sites would be horribly broken in IE. I sure wish we could do that--just agree to stop accomodating Internet Explorer so people would stop using it and the world would be a better place.

Unfortunately, people would blame us, not their browser, and stop visiting our sites.

Anyway, to Rod: I work at the English Language Center at Brigham Young University. Most of what I do is PHP w/MySQL, and Javascript here and there. http://www.elc.byu.edu/

I'm also working on the web site for the family business, but that's not up yet.

#237 Re: Maths Is Fun - Suggestions and Comments » Minesweeper MathsIsFun Style » 2005-12-04 19:37:35

A mathematical paradox.

In an 8x8 game, there are 64 total squares, right? And you start with 99 flags? and 99-64 = 35?

So what's wrong with this picture? (note, I was careful to see that every flag I dropped marked a square--I know that there are a few ways to drop the flag counter without marking more squares, but I avoided them).

#238 Re: This is Cool » Philosophy of math » 2005-12-04 18:40:14

"Philosophy and Math should not mix. Were it not so, Kepler's discovery of elliptical orbits would not have been controversial."

"Math is, more than any other subject, the training of the brain's logical and computational engines. For this reason, it's hardest to learn, requiring the most effort to master. For this reason, it's impossible to teach--every mind is unique, and must be trained in its own way; teachers of math must learn how to get out of students' collective way. For this reason, most people hate and fear math."

"Math is the tool that has built all societies."

All quotes by me wink.

I don't think Math should be called a science any more than engineering is a science. I don't see in it a natural law. Rather, it is a tool of our invention that allows us to describe and manipulate our world. It is the glue that holds all sciences together.

And, to mikau, I also think God is a mathematician. "The heavens, they are many, and they cannot be numbered unto man; but they are numbered unto me, for they are mine." -God

#239 Re: Help Me ! » math/physics relation » 2005-12-04 12:27:08

I'm in a college physics course that requires calculus.

#240 Re: Dark Discussions at Cafe Infinity » Firefox 1.5 Released » 2005-12-04 11:54:37

I checked it out yesterday. No Venkman. sad There are a few unofficial hacked versions out that claim to work, though.

#241 Re: Help Me ! » math/physics relation » 2005-12-04 11:47:05

Physics uses math to model reality. Some models work better than others. In that sense both are abstract, and both are real: physics is abstract until it accurately describes reality, and math is abstract until it is used to model real situations.

Don't get me started on Physics...(ignore air resistance and friction, my eye. Teach me something I can actually use, and then I might be interested.)

#242 Re: Help Me ! » Differentiation!!!!! » 2005-12-03 08:20:53

(π² * r^6 + 4100625)² / r  -  (π² * r^6 + 36905625)² / 3r

You will need to use the chain and quotient rules. Here are the pieces:
[ (π² * r^6 + 4100625)² ]′ = 2( π² * r^6 + 4100625 ) * 6π²r^5
= 12π²r^5(π² * r^6 + 4100625)

Quotient rule the first bit:
{  r * [ 12π²r^5(π² * r^6 + 4100625) ] - (π² * r^6 + 4100625)²  } /  r²

Now for the second bit:
[ (π² * r^6 + 36905625)² ]′ = 12π²r^5( π² * r^6 + 36905625)

{  3r * 12π²r^5( π² * r^6 + 36905625) - 3(π² * r^6 + 36905625)²  } / 9r²

Put them together:
( {  r * [ 12π²r^5(π² * r^6 + 4100625) ] - (π² * r^6 + 4100625)²  } /  r² )    -    ( {  3r * 12π²r^5( π² * r^6 + 36905625) - 3(π² * r^6 + 36905625)²  } / 9r² )

I'm sure you could simplify that quite a bit, but it's hard to see on a computer screen. smile

#243 Re: Help Me ! » Hard task! Need help! » 2005-12-02 10:38:37

Close. More like, "I can't woo her because whenever I see her I forget what I was about to say..."

Edit: or perhaps even more accurate, "I can't woo her because just looking at her make me forget what I was about to say..."

#244 Re: Help Me ! » Hard task! Need help! » 2005-12-02 10:28:37

Cool! What does that mean?

#245 Re: Dark Discussions at Cafe Infinity » Firefox 1.5 Released » 2005-12-02 10:26:59

Way cool.

I use Firefox primarily for web development, because the extensions are amazing (venkman, aardvark, web developer toolbar and the like). I'm waiting to DL it until I see if all my favorite plugs are supported, which I'd rather get paid to do than not. So, I'm waiting to do it at work. wink

#246 Re: Help Me ! » a bit difficult problem ... » 2005-12-02 03:45:19

My second thought is that it's using some sort of weird base system and representing it with letters. That's definitely not my forte, though.

#247 Re: Help Me ! » Hard task! Need help! » 2005-12-02 03:18:24

Except that, isn't it the standard to put the vertex of the angle in the middle of its name? So, would "PCB" and "ACB" both have their vertex at C? That would seem to make it easier to prove that the two are equal.

Don't you love these problems where nobody knows quite what they're asking?

#248 Re: Help Me ! » tough problem » 2005-12-01 18:20:14

But how am I supposed to know b and a were constants?

Mathematical convention. In the expression ax, a is the coefficient of x.

BTW, since a is not a function (but a constant), you use the constant multiple rule. That is, (a*f(x))′ = a * f′(x).

Hey, I've got it! That was a tricky bit of algebra.

We have (b-a)e^(bx-ax) = be^bx / ae^ax
Now, (b-a)e^(bx-ax) = (e^bx / e^ax) * (b-a)
and be^bx / ae^ax = (b/a) * (e^bx / e^ax)

Our expression is now (e^bx / e^ax) * (b-a) = (b/a) * (e^bx / e^ax)

Cancel out the e's to get b-a = b/a. Solve for b:
b = ab - a²
a² = ab - b
a² / (ab - b) = 1
a²b / (ab - b) = b

b = a² / (a-1)

The stuff you come up with, I swear...:P

#249 Re: Help Me ! » tough problem » 2005-12-01 15:51:20

f'(x) = e^bx * (b+x)    g'(x) = e^ax * (a+x)     Correct? Did I do that right?

Nope. (e^bx)′ = (e^u)′(bx)′ = be^bx. (That's the chain rule.) The same goes for e^ax.

We know that (e^bx / e^ax)′ = be^bx / ae^ax. That is,
(b-a)e^(bx-ax) = be^bx / ae^ax

At this point, I got lazy and told my calculator to solve that for b. It spat this out:
b = a^2 / (a - e^2ax)

That's as far as I can go with it.

#250 Re: Help Me ! » Hard task! Need help! » 2005-12-01 14:33:15

Is this an accurate representation of the problem?

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