Ten is the lovliest number... - by Nicker
Nicker on 8/10/2023 at 19:19
...or is it?
What is it about base ten? Does it actually have a special symmetry or is it just dear to humans because we have ten digits?
Orders of magnitude can be effected by moving the decimal place. To this matho-phobe, that is an elegant capability which seems unavailable to other number bases. True or false?
There are doubtless many gaps, errors and misunderstandings even in how I frame this question, so please don't take my statements as a fixed position, just a starting place. If anyone cares to help unravel this mystery (if it is one), I would love to hear.
Many ancient numbering systems are based on sacred numbers; the seven visible "planets", the six male deities of the Babylonians, (possibly morphing into the twelve apostles, etc.).
The Imperial system is a mad mashup of base four, with base twelve used for quantity, weight and distance but base sixteen used for fluid measures. Except of course for British human weights measure being base fourteen (a stone). It wasn't until the 1800's that Britain attempted to systematically inter-relate these different measurement magisteria with reference to common materials (for example, a gallon becoming ten pounds of distilled water at 62 degrees Fahrenheit and 30 inches of mercury.
Even though we derive our decimal terminology from the Romans, their military units were generally organised on multiples of eight, occasionally alternating with multiples of ten or six. A century was eighty men, a cohort was 480 men and a legion of 4,800 men. This despite their mercantile and engineering calculations being done in quinary (base five) and decimal (base 10) as evidenced by the pocket calculators of the day. Apparently, Roman and Asian abacuses were ultimately binary and other cultures used similar calculating frames based their own culturally informed number bases.
The ancient Chinese organised their armies on multiples of five while the Mongols used strict decimal increments when scaling up from the basic squad.
Pyrian on 8/10/2023 at 19:46
Quote Posted by Nicker
...is it just dear to humans because we have ten digits?
Bingo.
Quote Posted by Nicker
Orders of magnitude can be effected by moving the decimal place. To this matho-phobe, that is an elegant capability which seems unavailable to other number bases. True or false?
You can move a decimal place in any base. We use "order of magnitude" as "power of ten"
because we use base 10.
demagogue on 8/10/2023 at 20:02
Just yesterday the YouTube channel 3Blue1Brown released a (
https://www.youtube.com/watch?v=6a1fLEToyvU) summary video of top SoME3 entries (3rd annual Summer of Math Explanations or whatever it stands for), which I watched (and recommend to anyone with even a passing interest in math), as well as some of the entries I liked.
One of them brought up the arbitrariness of base 10 and was asking the question if our entire real number line is arbitrary, or is there something special about it no matter what base you use.
If you're going to drop a thread like this, I may as well (
https://www.youtube.com/watch?v=uFWJuZQLKJs) link to it, since it's in the neighborhood and gives you a sense of what is and isn't arbitrary about numbers.
Nicker on 8/10/2023 at 20:37
Thanks for the replies. I have often wondered about this matter but lack the knowledge to even construct the question properly, and therefore to research it effectively.
OK, I'm lazy. Thanks for indulging me.
heywood on 9/10/2023 at 12:37
That's a cool visualization.
Would love to see that extended to complex numbers.
Nicker on 9/10/2023 at 16:37
The visualizations are indeed amazing. I wish I had been exposed to more such visual aids in school. My friend, who was far more numerate than me, remembers his teacher using such aids, like a set of wooden blocks like these...
Inline Image:
https://www.tutoringforexcellence.com.au/wp-content/uploads/2015/11/1.pngThe amount of understanding contained in this simple device is astounding. He said he remembers the instant of realization it brought him as a small child.
I remember the instant I gave up on math in high school. After weeks of solving geometrical equations, I could not remember the last time I had seen a geometrical shape, either in the geometry text book, or on the blackboard or in my head. I was crap at calculation and all the joy just drained out of me.
I hope this thread might reignite some of the curiosity I lost. And I am grateful for any enthusiasm that people share here.
demagogue on 9/10/2023 at 17:34
For complex numbers, which heywood asked about, visualization can be tricky. Every value is a place on a 2D grid x + iy. The x is the real line, but there's every value ∞i to -∞i added to it to make a single value modeled as a single point on that grid, so that's what the complex number space looks like. You just can't "line them up" as easily to know what it means to move around in that space.
I actually think it's often better to think of them like vectors (arrow with its tail nailed to the origin) in a radian circle grid with a magnitude (distance) from the origin and an angle from the x-axis, which has the advantage of the angle just being between 0 to 2pi, and you can use the exponential and Euler's Business, which just means it really simplifies the math for certain kinds of problems. In particular, it's good for modeling things that go through regular cycles like waves, wheels, pendulums, orbits, walking, economies, etc., where the angle part of the vector models the place in the cycle a thing is at some point (what they call phase), and if you take that trick and spin it, when it reaches 2pi it automatically is reset to zero for the next cycle.
Complex numbers add like vectors. But they multiply weirdly. For real values, multiplying extends or shrinks the input as normal. But multiplying by i works like you're spinning a vector 90 degrees CCW by definition: 1*i = i, i*i = -1, -1*i = -i, and -i*i = 1, which normally wouldn't seem useful, but again if you're modeling anything that cycles, that's really useful.
Anyway, it's a little easier to imagine "lining the numbers up in a sensible way" with that idea, though still a little tricky.
And that's just imagining the imaginary number space itself. Trying to visualize functions, which map from one number to another number, is a whole other bag of worms!
For real functions, you just imagine a line on a Cartesian grid, giving you a y output for every x input. But for complex functions, for every one-number-two-value input you have to give a one-number-two-value output, plus that business that multiplying by i spins the whole thing CCW.
You can put both the 2D input and 2D output onto the same 2D grid with arrows from the input to output, or by redrawing the input grid on to the output grid, or you could use color or the third dimension to give you an extra dimension each. Actually I watched a (
https://www.youtube.com/watch?v=NtoIXhUgqSk) video that I liked recently walking through the different visualizations.
Pyrian on 9/10/2023 at 18:24
Quote Posted by demagogue
Complex numbers add like vectors. But they multiply weirdly.
I feel like complex numbers multiply more normally than vectors, lol. Complex multiplication is just... Multiplication. (With i.) But there's two different vector products (dot product and cross product) and
neither of them are really all that much like normal multiplication at all. The dot product of two vectors isn't even a vector, and cross products aren't commutative (or rather they're "anti-commutative" so V1 X V2 = - V2 X V1).
demagogue on 9/10/2023 at 19:21
As I was saying, they don't multiply like vectors. I was just going from the previous sentence when I worded it that way, though, when like you say it's probably not worth bringing it up in the context of vectors at all... So it's good you pointed all of that out.
I really shouldn't be explaining complex numbers or analysis at all, since I haven't really digested it yet, and I bet I misworded or got a good amount of stuff outright wrong.
But I'm talking about it because I'm studying it these days, since I really want to finally understand quantum mechanics this year (as in be able to actually solve homework problems), and complex analysis is its bread and butter. And I'm always looking for intuitive ways to ... well it's really too ambitious to think you can visualize this stuff, but at least have some good working metaphors and mental images that can help.
But it's such a high when I get a homework problem right, or anyway I do the steps correctly and an answer pops out. I was starting to assume I'd get all of the homework wrong, but a few days ago I was going through the motions for finding the expectation value for something called the infinite square well, assuming as usual it was all wrong and I'd have to see where I went off, when suddenly the right expectation value just popped right out, length/2. I mean I knew it was right because it's easy to intuit it before you even start the problem. But to see it actually pop out of the mess gave me a real high at the time.
It's really like magic, since in the thick of it you think none of this is going to end up anywhere but a big mess, and then like magic all these terms start suddenly canceling and simplifying and a meaningful solution pops out and has a real meaning.
I was one of those liberal arts students that still took calculus up to Calc3 in university & a few other advanced math classes. There were a handful of us doing that. It's a specific type of personality that wants to be rigorous and flexible (as in understanding that history and politics are messy and come as they go) in their thinking at the same time. But I kind of hated that it was just pointless number or symbol pushing. I had an intuition if you were doing it to actually answer a real world problem, that would make the symbol pushing really come alive like a kind of magic, and doing physics homework helps with that feeling. That's how I felt about game programming too (like the work I did for Dark Mod); where you're trying to solve a puzzle that actually does something interesting to the world. (I was working on the sound system, which you all know is a big part of stealth gameplay.)
Any kind of physics can do it, I guess, but I kind of hated high school physics because my teacher didn't bring any of the magic out. It all seemed so arbitrary or not very enlightening. It got a little better with electromagnitism, which the math helps make some sense of it and you can understand some modern tech. But quantum physics is on such a different level of having bewilderment and magic in the math while still following rules in a logical way. Well I don't want to derail this thread when we're starting with the magic of base ten. XD But maybe it will help on the inspiration end.