Too creepy. Waaay too creepy.

[Dav3ey]

Dontcha think?

Mind Probe

Hmmm.

[veeco]

I'm not sure how it works, mathematically, but no matter what number you choose, it's always going to end up on the same symbol which is repeated quite often in the table...

Maybe EDEW or Epeemike who are Math experts can explain...

[Dav3ey]

True -- I think that I would have been laying in bed staring at the ceiling all night if I hadn't noticed that.

It seems that one will always arrive at a multiple of 9 when you do their math -- and of course all those figures are the same.

But until I got it, I'll admit to being a little flipped out.

If there's anyone out there who's familiar with accounting they'll know that there's an accounting check that involves the misplacement of an entry giving rise to a mis-balance of a multiple of nine.

Besides, it's a fun link to e-mail to your gullible and conspiracy-focused pals. Well, fun for you, at least -- and isn't that what it's all about?

[veeco]

Hey, once I figured it out, what do you think I did? I had to have my girlfriend try it out and see if she could figure it out by herself!

[Aoife]

lol, okay, I had to mess it up. The shape I got didn't show in the box, and I felt triumphant that I had fooled the program. Then I realised my maths was wrong.

Once I got the maths right I saw the line in the multiples of nine. (It's easy to see if the symbol which comes up is a solid black one, but harder to see if it's one of the less distinct symbols)

I love this kind of thing, gives my mind a run-about (technically the RS essay I went onto the computer to do would also do that, but I get easily distracted )

[epeefencer74]

you can do some pretty interesting stuff with multiples of nine. This one is new though, I didn't know that subtracting the 2 digits of a 2 digit number from the number itself resulted in a multiple of nine.

[Aoife]

I know what useless trivia I'll be bringing up in my next maths lesson.

And my next fencing lesson (especially considering my coach is a maths teacher for a living ).

[Dav3ey]

Aoife -- I'm not surprized at all that your fencing coach is a math prof. One of my coaches (well, more of a coach-emeritus who felt sorry for me and gave me some extra attention!) was also one of my math prof.s

Just before a DE bout that we had -- and that he would have won comfortably anyway -- while we were testing weapons,
he said, "Did you know that e^([pi]*i)+1=0?"
Me: "No way."
Him: "It's true."
Me: "What is that, a hunch?"
Him: "Nope."
Me: "You can prove that?"
Him: "Of course."
Me: "How."
Him: "You tell me and I'll give you an A in your mathematical statistics class and exempt you from the final."
After about three minutes, it was
.
.
.
2-15.

And, sorry, but I couldn't prove it either. He had pity on me and explained it -- and told me that someone had explained it to him too.

BTW -- I notice that the UK'ers abbreviate "mathematics" as "maths" whereas those of us on this side of the pond use "math". A bit odd if you ask me, since I think that Brits tend to use nouns as collective plurals, e.g., "Arsenal are going to beat Man. U.".

[Swordsman]

I want to know who noticed, how they noticed, and how they have so much spare time - that subtracting from a two-digit number its constituent numbers always yields a multiple of nine. Just a quirk of the decimal number system, I'm sure...but who bothered to sit down and figure it out (let alone code that thing)?

[Aoife]

I notice that the UK'ers abbreviate "mathematics" as "maths" whereas those of us on this side of the pond use "math".

lol, that might just be me.

*runs off and checks*

Nope, apparently we says 'maths' because of the 's' on the end of 'mathamatics'.

I'm not surprized at all that your fencing coach is a math prof. One of my coaches (well, more of a coach-emeritus who felt sorry for me and gave me some extra attention!) was also one of my math prof.s

Maybe it's some sort of maths teacher conspiricy (although, to be honest, I can't see any of the other four maths teachers at my school being particularly adept at fencing )

How would you actually say e^([pi]*i)+1=0? Thanks.

I want to know who noticed, how they noticed, and how they have so much spare time

Swordsman: I have wondered this about every mathamatical rule I've been taught. I've long held the conviction that Pythagoras and co. had far far far too much time on their hands

[Dav3ey]

The expression looks worse here because I can't type an actual math(s) expression.

One would say "e to the pi i plus one equals zero".

Forgive this if you know, but
e is the irrational, transcendental base of the natural logorithms,
pi (usually written using the lower-case Greek letter) is the irrational, transcendental ratio of the circumference of any circle to its own diameter, and
i is the imaginary number that, when squared, gives us -1.
Stunningly, if you take e and raise it to the power of the product of pi and i, this equals negative one. Add one to both sides and you have e to the pi i plus one equals zero -- an expression that, as John Paulos notes in his book Beyond Numeracy, is an elegant relationship between four of the most basic elements of mathematics.

As for Pythagoras, remember that in ancient Greece, only Greek male land owners counted -- everyone else was a slave, a woman, or hoi poloi. If we were part of that caste, we'd have lots of free time too. Might even solve Fermat's Last Theorum!

[Dav3ey]

Oh, and "pi" is pronounced the same as "pie", like the dessert.

[magma]

This was really good, i dont want to lose this little 'card game', i have to add it to my favorites. i like these sorts of things.

[magma]

Post Scipt
the british say lots of funny things, like: chemist for pharmasist; most of my neighbors were from either england, australia or new zealand, they were great people; a 'length' for a meter etc.,

are irrational numbers : real numbers as Ions : elements? I don't remember what an irrational number is. thanks.

[magma]

i like this even better than originally, because the squares change every time you pick one.

[Dav3ey]

Yeah, those English! They think they're just soooo superior!
javascript:smilie('')
I recall once at a party, this poor fellow from England was telling this story about how he and his friends would play "torch tag" as kids. "You know, run around at night with torches, trying to get each other." He could tell from the horrified looks on people's faces that his point hadn't gotten across -- until I filled folks in that this was just the same "flashlight" tag we play in the US. I also had to explain to him the image that "torch tag" evoked for us. Everyone was much relieved.

And an irrational number is a number that cannot be expressed as a fraction x/y. Like 6 can be written as 6/1, hence, rational. But the square root of 2 can't be, hence irrational. Any regular number, fraction, or decimal that terminates (like 0.125=1/8) or repeats (like 0.6666...=2/3) is rational. Irrational numbers are decimals that never end and never repeat.

Also, a transcendental number is a number that isn't the solution to any quadratic equation with interger co-efficients. So 6 can be written as x^2=36, hence not transcendental. And the square root of 2 can be x^2=2 -- also not transcendental. But e and pi can't be, so they are. (How do we know? 'Cuz guys way sharper than yours truly say so. I'm not even sure how one proves transcendence.)

So when you throw two of these, plus the imaginary i into the mix and come out with a number that's not just real, not just rational, but a regular old integer (-1), it's just a math gem.

[Dav3ey]

Whoa. I got a look at my last post...and had a "Boy, I sure can be square!" moment.

[thinks]

No...wait...I think I'm cool.

[thinks]

Yup...I'm right. I am cool.

[Aoife]

I've very impressed. I'm going to have to learn this as a party-piece (not one of the most alluring party pieces in the world, but one which is very me: nerdy )

I've always known about pi being irrational and transendental, and I'd heard of i before, but e is still confusng me a little.

e is the irrational, transcendental base of the natural logorithms

Meaning? (sorry to sound a little dense, but maths is my weekest subject ) It's the 'natural logorithms' part which I'd love clarified. Thanks.

Oh, and one last acknowledgement of my status as 'school-student-who-pays-little-attention-in-maths'.

e to the pi i

In the computer symbols you've said '^' respresents 'to the', but what would represent that in writing? (sorry, I know it's hard to describe sometimes). Is it supersript? As in 'to the power of'?

Thanks a million.

[Danzan]

Originally posted by Aoife
It's the 'natural logorithms' part which I'd love clarified. Thanks.

A natural logarithm is a logarithm in base e. (E is simply the sum from 1 to infinity of 1/x!, or in other words, 1/1!+1/2!+1/3!, etc. "!" is the factorial, where you multiply that number by all preceeding (whole) numbers back to one. So 3! is 3*2*1, or 6) It's about 2.7182

A logarithm (in case you are rusty) is basically the exponent. So if 100 = 10^2, log (100) = 2, and log (1000) = 3, assuming a base ten system.

Natural logs (usually denoted ln) work in base e instead of base 10. So ln (e^2) = 2. They used a lot in science - as I recall, things like various decay rates and all sorts of engineering equations use them. They are also used in some financial situations, since they can be used for determining continuously compounded interest.

It's also fun because, if I remember correctly, the derivative of ln(x) is simply 1/x, so at times in complex math(s) you can basically convert to base e, do the math, and convert back. (or something like that.) Saves lots of time. In theory.

And yes, "^" would be written as a superscript - it is the "to the power of" symbol.

Hope this didn't confuse things more. And that someone will (gently) correct the errors, if any. A) I need to go make more coffee and B) it's been over a decade since I've done this stuff, but thought I'd try an answer as way of avoiding other work.

chris

[Dave]

Any decimal number can be represented as

10*a + 1*b


where a and b are the first and second numbers.

If you then subtract the sum of a and b (IE what you have to do for the test) you have

10*a +b - ( a + b )


= 10*a -a + b - b

= 10*a -a

= 9*a




Dave

(Who is spending his sunday in lab and needs anything to distract him)