and you are some kind of physicist too, right?

Don't knock the old mathematics caper, it's brilliant stuff.
I like the number i, which is the square root of minus one
completely imaginary, but essential.
I have been watching an excellent series on TV called "The Code"
I was discussing this with my elderly mother and we were discussing different number
systems, eg Decimal, Binary and Hexdecimal ( base or radex 16 ) when she piped up
with the info that mathematicians have another system that uses base 12
as in decimal 10 is only divisible ( in whole numbers ) by 5 and 2
whereas this base 12 caper is more useful because 12 is divisible ( in whole numbers )
by 3, 4 and 6
Has anyone else heard of it ???
Apparently there was an ancient civilisation in the general "Persian" area that
used a base 60 numbering system, derived from there astronomical "knowledge",
that they then used for "everyday" maths, symbols on clay tablets stuff.
I wonder if anyone has heard of that.
The romans might not have a digit to represent zero, and the idea of having a zero
is apparently from the Indian or Sri Lankan's

@YJ

I'm an EE. I make models of quantum structures.

MRIs are some cool shit.

I thought the Incans did zero first?

ahh... EE, like a physicst, but employable.

Good for you!

Base 12 is nice, though base 6 is equally useful, base 10 is really pretty useless. The Babylonians had a base 60 numbering system, but all of their numerical symbols were made up of ten others, so their system was really very similar to base 10. The Romans sucked at math (no 0, they approximated pi as 3). I think you're right about the concept of zero originating in India, though the Mayans had similar ideas independently and the Greeks struggled with the concept philosophically.

That's a very apt description, YJ.

no, it = 0. Always truncate, bro.

@YJ

LOL

Yes, that's a very good description of EEs.

"I like the number i, which is the square root of minus one
completely imaginary, but essential."

I'm sorry, I'm not familiar with "i". Perhaps you mean the imaginary number j? : )

@abge "i" is another one that nobody ever uses, i=jk and -i=kj

That help?

0.99....... doesn't exist. that's what i say. math has this bs about a number with an infinite number of digits which is nonsense. there are only countably many numbers in the universe and 0.99.... ain't one. if it did exist it would be 1 though.

@bolshoi

You know what wouldn't work without Math BS?

Power Plants and AC electricity, Computes (any modern electronic device), GPS, Signal/Image Processing, fluid dynamic problems, etc.

You think that there is a countable number of numbers? Even without infinite decimals the number of numbers is infinite. On top of that, you can't deny the existence of numbers like 1/3, pi, and e, while living in a world where those numbers impact everything around you.

i think there's some paradox related to this. you shoot an arrow, it travels 9/10ths of the distance to a tree, but then out of the remaining distance it has to travel 9/10ths and then 9/10th of what remains. so the arrow never reaches the tree, so the distance is never 1 so 0.999.... does not equal 1. QED.

when i say countable, i mean countably infinite. mathematicians talk about countable sets whose size is equal to the number of integers (which is infinite). but the number of real numbers is larger than the number of integers, so they are not "countable". sorry about the confusion. i still mean an infinite number of numbers.

Actually, it reaches 1 after traveling 9/10 of the remaining distance an infinite number of times. Somebody, I think semck, already used that as an example, though he didn't bother with the real world situation.

.9999 = 1 if you can make it fit your formula.

Yeah, another way of thinking of it is as an infinite sum of decreasing values that brings 0.9999... infinitely close to 1. Infinitely close, in math terms, is the same as equality I believe. It's like this:
Sum (n=1 to infinity) 9x10^-n
apologies, but sigma notation isn't so easy to type :P

"so the arrow never reaches the tree"

And yet bows and arrows were used for 10,000 years as the most advanced form of warfare and hunting, so that would lead one to suspect that the arrow does, in fact, eventually make it to its target. : )

I really don't see how this is even an argument, it's an indisputable fact.

in my opinion 0.99... = 1 in the same way 1/infinity = 0. both these statements are strange since they both contain numbers defined implicitly on the left hand sides. when i say "all this math bs" i'm not talking about useful math that explains and predicts. i'm talking about people taking theory and extending it to a philosophy.

bolshoi, the decimal 0.999... is PERFECTLY well defined. It is defined as an infinite sum, and its value can be rigorously calculated. zultar already did this very early in the thread. This is not "philosophy" math, it's mainstream math. I'm sorry you don't understand it, but I'm sorry, your arguments are laughable.

When I was a kid in the '60s we were introduced to decimals *after* we'd mastered fractions - adding, subtracting, multiplying and dividing them - something that isn't taught to any useful level these days.

One of the ideas the teacher made sure we got was that fractions are accurate but decimals are generally approximations. Example: 1/3 + 1/6 = (2/6 + 1/6) = 3/6 = 1/2, which is an entirely accurate answer; but if you use decimals you get 0.333333 + 0.166666 = 0.499999, which is close, but wrong. You have to round 0.166666 up to 0.166667 in order to make it work, but 0.166667 isn't 1/6 any more than 0.166666 is, it's just an approximation to make the maths work. Worse, 0.333334 + 0.166666 = 0.5 too! The more "33333"s and "66666"s you use in these approximations the closer you get to an accurate answer, but you need to keep them going forever in order to get a truly accurate answer and that's impossible.

Well, STA, if you just put a bar over the last digit in this equation

0.333333 + 0.166666 = 0.499999

then it is completely right.

i didn't say it was not defined, i said it was implicitly defined. that is, not calculated out. 0.99... doesn't exist as a number, it only exists as an infinite sum.

then again i guess i would call 0.55... a number. so maybe my definitions are a bit strange. but if 0.99... is a number then that number is 1. or are they separate numbers that are equal?

what if you have two "numbers" that are only defined as infinite sums and you're not sure if they are equal? or it can't be determined in our universe if they are equal? then are they equal or not? if a tree falls in the woods does it make a sound?

actually i meant are they the same number or not.