Why does this symbol exist ÷

Question

yoloshroom · Answer

To show division? :O

empty · Answer

Yeah but doesn't this show division already /

anonymous · Answer

Probably for when you first started math so you didn't get / confused with brackets..lel

doggy · Answer

because the subtraction sign wanted piercings

jim_thompson5910 · Answer

https://en.wikipedia.org/wiki/Obelus

unklerhaukus · Answer

$$5/2 = 2.5$$$$5\div 2 = 2$$

yoloshroom · Answer

remainder vs exact?

ganeshie8 · Answer

wolfram seems to treat both the symbols same historically they have different usage though : $3\div 2(2+3)$ is interpreted as $\dfrac{3}{2(2+3)}$ $3/ 2(2+3)$ is interpreted as $\dfrac{3}{2}(2+3)$ https://books.google.co.uk/books?id=ZJg_AAAAcAAJ&printsec=frontcover&hl=en#v=onepage&q&f=false

ganeshie8 · Answer

http://www.matthewcompher.com/posts/trouble-with-semantics-the-obelus-or-division-symbol-%C3%B7/

ganeshie8 · Answer

i'd assume that  parenthesis was probably not so popular to group things at that time...

skullpatrol · Answer

Having two symbols for the same operation is not unusual, consider X and * for multiplication.

empty · Answer

True, but after a certain point it seems like everyone seems to adopt the same sort of notation, where they only use fractions and drop the multiplication sign altogether.

I guess my main problem with this ÷ is that it seems like its only purpose is to confuse people with PEMDAS or whatever, and shouldn't be taught since it ends up introducing confusion where it doesn't have to be if we just all used parenthesis.

empty · Answer

Maybe I'm wrong, maybe it's necessary to have a division sign ÷ and it's a stepping stone that everyone uses at some point. It's really been too long ago since the last time I used this symbol to even remember a time where I actually used it.

skullpatrol · Answer

Indeed, the symbol is used in connection  with teaching the method of long division in early elementary school. As long as the definition: $$a\div{b}=a/b$$ there "should" be no confusion :-)

empty · Answer

Just because I've never seen it, and likely no one else has too, here it is folks:

$$\int_a^b( 1 \div x) dx$$

skullpatrol · Answer

:O

empty · Answer

I call this the 'child physicist's Leibniz notation'

$$dy \div dx$$

parthkohli · Answer

$$= \ln (b \div a )$$

parthkohli · Answer

or just to mess with you$$\log_e (b \div a)$$

empty · Answer

$$\partial f \div \partial x \times d x \div dt + \partial f \div \partial y \times dy \div dt$$

parthkohli · Answer

I think I just puked a little...

empty · Answer

Just the good ol' fashioned chain rule
$$dy (dt)^{-1} =  \partial y ( \partial x)^{-1} dx (dt)^{-1}$$

jim_thompson5910 · Answer

It only looks bad because you're used to dy/dx instead of the other format. Although the slash is a bit more compact and it's on the keyboard

the $\Large \div$ symbol is useful to break up the monotony of having too many divison bars

example: instead of $\Large (2/3)/(5/7)$ it might be easier on the eyes to write $\Large (2/3) \div (5/7)$

skullpatrol · Answer

If you are mathematically mature enough to handle Calculus, 
then you will use symbols that are the most concise and the obelus is forgotten :P

skullpatrol · Answer

Note also your avatar @Empty  can be written as {}.

empty · Answer

$$\Huge \varnothing$$ looks nicer! Although I have a little reference to the ridiculous silly way of counting with empty sets inside of empty sets in my profile with that notation lol

ikram002p · Answer

its for kids :P

ikram002p · Answer

the history behind it is to simplify arithmetic for non mathematician assuming there is 4 arithmetic operation which are div,mult,add,sup
while mathematically there is 2 add,mult