# Maths Question about Braces ({[]})

• 09-30-2004
Davros
Hi there,

What is the proper distinction between the different brace/parenthesis notations:

Code:

```{} [] ()```
when used in math (not programming)?
• 09-30-2004
Perspective
This depends on how they are used. here are some common ones

{} - used for set theory ex. { x | f(x) < 4 }
() - used for function notation as shown above f(x)
() - used for order of operations ex. (3 - x) * ( (x / 2) / y )
() [] - used for exclusive/inclusive intervals ex. [3, 6) Three to six including 3 but not 6
etc...
• 09-30-2004
Davros
Good stuff. Thanks.
• 09-30-2004
ZakkWylde969
Quote:

Originally Posted by Perspective
() [] - used for exclusive/inclusive intervals ex. [3, 6) Three to six including 3 but not 6
etc...

:confused:
• 09-30-2004
KneeGrow
Quote:

Originally Posted by ZakkWylde969
:confused:

No no, what he means is that if you have a graph of like a Domain or Range you write

[-5, 3) that means all numbers work from -5 to 3 but 3 is not included so basically everything between -5 to 2.999999999999
• 09-30-2004
ZakkWylde969
Oh ok. That's really cool actually. No longer will I have to write everything then add another

x =/= #
• 09-30-2004
axon
[] also used for evaluating integrals with the limits writen in the upper and lower corner of the "]" - I've seen some text books do it.
• 09-30-2004
Zach L.
[] are occasionally used for () in order-of-ops for clarity reasons (I do this often). E.g. ([4x * (3 - 2x)] / 6). I've never seen {} used that way, though. Also, {} is sometimes used for series notation. E.g. {a^i} with a lower limit on the bottom corner of the '}' and an upper limit on the '}' (if applicable).