1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Using divide as a 'sign' for a number

  1. Aug 20, 2010 #1
    A negative number has the minus sign as its own intrinsic operator. Has anyone thought of using the divide symbol in a similar way, and has there been any attempt to standardize this throughout math?

    For example (assuming / is the divide symbol):
    /5 = reciprocal of 5 = 1/5 = 0.2.

    It saves having to always use the "1 divided by" bit in 1/x.

    One can then even use two divides to cancel each other out. Example: //5 = 5 (just like --5 = 5)

    Good idea?
     
  2. jcsd
  3. Aug 20, 2010 #2

    cepheid

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    People use an exponential notation instead:

    1/5 = 5-1

    (5-1)-1 = 5

    Edit: By the way, you typically have to write -(-5). If you write --5, most people won't know what you're talking about.
     
  4. Aug 20, 2010 #3

    Mark44

    Staff: Mentor

    Unless you're writing bad C code that is attempting to predecrement a constant:biggrin:
     
  5. Aug 20, 2010 #4

    cepheid

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    LOL, that thought totally occurred to me as well. :wink:
     
  6. Aug 20, 2010 #5
    Yes.

    I still think my idea is more consistent with the idea of a negative sign (I code in C quite a bit too, so maybe my inspiration stems from there, since encoding the division sign in a number would be quite elegant in some cases).

    It also means you can have stuff like:

    /5 *10 = 2
    10 /5 = 2 (or maybe 10*/5 = 2, and no that isn't a C comment closing tag).

    So I've swapped the 'numbers' around, and achieved the same result, meaning we have commutativity just like with multiplication. We can even treat *10 = 10 (just like +10 = 10). Has nobody really thought of this crap before?
     
    Last edited: Aug 20, 2010
  7. Aug 20, 2010 #6

    Mentallic

    User Avatar
    Homework Helper

    I'm pretty content with the way it is at the moment. We already have various ways to represent reciprocals, that being [tex]\frac{1}{x}[/tex] and [tex]x^{-1}[/tex]. As for the minus operator, we don't really have many other ways to express it, so we need at least 1 way to show the negative of a number. We don't need more ways to express what we already have for reciprocals though.

    As for ease of typing, [tex]x^{-1}[/tex] is pretty easy isn't it?

    I wouldn't be surprised if it were implemented in some coding language, but in terms of making it standardized in mathematics, nah dont need it eh
     
  8. Aug 20, 2010 #7

    Hurkyl

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I think it's standard for the arithmetic of a wheel. But there, it's an operation in its own right (a total one, in fact) rather than being an inverse to multiplication or similar kind of thing.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook