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 Monox D. I-Fly July 7th, 2014 04:06 AM

Difference of Mathematics Notation System

Regarding my previous thread, I want to discuss if there are other instances of the difference between mathematics notation system all over the world. In my country (Indonesia), there are several examples. Most notably:
1. To note "one thousand", most people write "1,000" while Indonesian write "1.000".
2. To note "four point eight", most people write "4.8" while Indonesian write "4,8".
For quite some time, I thought it was only in my country. However, later I found out that several other countries (though I totally forget which of whom) also use this kind of notation system.

And then, in my previous thread I found out that most people in the world write "base 2 log of 3" as "$\displaystyle \log_23$" while my country writes it as "$\displaystyle ^2\log3$". Are there other differences between our notation system? Let's discuss.

 matthematical July 7th, 2014 07:35 PM

I live in the US. It seems like the comma-and-decimal-point systems in our two countries are reversed. Here in the US, we use a point for decimals, while in Indonesia, you use a comma for decimals. Here in the US, at least in basic math classes, we use a comma for thousands, etc., while in Indonesia, you use points. Interesting!

You mentioned "base log 2 of 3." I say it as "log base 2 of 3." I don't know if this is standard in the US, but it's how I say and teach it.

In Indonesia, do you use all of the same notations we use in the US for higher mathematics? I.e., inclusion symbols
$\displaystyle x \in A$
$\displaystyle A \subset B$

And sets of numbers, i.e. $\displaystyle \mathbb{R}$, $\displaystyle \mathbb{Z}$, etc.

 Monox D. I-Fly July 7th, 2014 09:13 PM

Quote:
 Originally Posted by matthematical (Post 199668) In Indonesia, do you use all of the same notations we use in the US for higher mathematics? I.e., inclusion symbols $\displaystyle x \in A$ $\displaystyle A \subset B$ And sets of numbers, i.e. $\displaystyle \mathbb{R}$, $\displaystyle \mathbb{Z}$, etc.
Yes, we do. We also use those symbols in mathematics. $\displaystyle \mathbb{R}$ is for real numbers, right? Though some of us tend to use normal R instead which sometimes confusing due to not being able to distinguish it from the rational numbers. We do use $\displaystyle \mathbb{Z}$, though I forget in which set of number it is used. If I recall correctly, it's the notation for integers, right?

 CRGreathouse July 8th, 2014 06:13 AM

Writing numbers as 1.234.567,89 is pretty common, even if the US-style 1,234,567.89 is more common still. I've never seen $^2\log3$ and would advise you to not use it online where it will only lead to confusion.

But then again I tend to prefer $\log3/\log2$ anyway, and if you write that there's no confusion.

 Monox D. I-Fly July 8th, 2014 06:32 AM

Quote:
 Originally Posted by CRGreathouse (Post 199712) Writing numbers as 1.234.567,89 is pretty common, even if the US-style 1,234,567.89 is more common still. I've never seen $^2\log3$ and would advise you to not use it online where it will only lead to confusion. But then again I tend to prefer $\log3/\log2$ anyway, and if you write that there's no confusion.
So, is not there any other country than Indonesia which use $^2\log3$ ?

 matthematical July 8th, 2014 07:26 PM

Quote:
 Originally Posted by Monox D. I-Fly (Post 199671) We also use those symbols in mathematics. $\displaystyle \mathbb{R}$ is for real numbers, right? We do use $\displaystyle \mathbb{Z}$, though I forget in which set of number it is used. If I recall correctly, it's the notation for integers, right?
Yes. We also use $\displaystyle \mathbb{N}$ for the natural numbers, $\displaystyle \mathbb{C}$ for the complex numbers, and $\displaystyle \mathbb{Q}$ for the rational numbers.

Also, you might see $\displaystyle \mathbb{W}$ for the whole numbers and $\displaystyle \mathbb{H}$ for the irrational numbers.

 Monox D. I-Fly July 9th, 2014 03:42 AM

Quote:
 Originally Posted by matthematical (Post 199777) Yes. We also use $\displaystyle \mathbb{N}$ for the natural numbers, $\displaystyle \mathbb{C}$ for the complex numbers, and $\displaystyle \mathbb{Q}$ for the rational numbers. Also, you might see $\displaystyle \mathbb{W}$ for the whole numbers and $\displaystyle \mathbb{H}$ for the irrational numbers.
Thanks for the information. Btw, I'm curious about why $\displaystyle \mathbb{Q}$ and $\displaystyle \mathbb{H}$ were chosen to represent rational and irrational numbers, respectively while the other notations are only taken from their initial letters.

 matthematical July 9th, 2014 06:09 AM

I'm not sure, although the Q symbol might be a reference to "quotient."

 Monox D. I-Fly July 9th, 2014 08:06 AM

Thanks.

Oh yeah, I noticed one more thing:
Back then, someone is this forum said that if you write log2, then the base number is e. Is that true? Because in my country, if the base number isn't written, it is considered as 10 instead.

 CRGreathouse July 9th, 2014 10:44 AM

Quote:
 Originally Posted by Monox D. I-Fly (Post 199718) So, is not there any other country than Indonesia which use $^2\log3$ ?
Not that I know of.

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