Difference between different types of brackets used

This topic has 1 expert reply and 3 member replies
winnerhere Master | Next Rank: 500 Posts Default Avatar
Joined
12 Apr 2007
Posted:
231 messages
Followed by:
1 members
Thanked:
5 times

Difference between different types of brackets used

Post Thu Sep 03, 2009 5:19 am
Elapsed Time: 00:00
  • Lap #[LAPCOUNT] ([LAPTIME])
    Whats the difference between square brackets,parenthesis and flower brackets in mathematics

    [0,5]

    (0,5)

    [0,5)

    are all different ranges.

    Thanks in advance Smile

    Need free GMAT or MBA advice from an expert? Register for Beat The GMAT now and post your question in these forums!
    DanaJ Site Admin
    Joined
    01 Jan 2009
    Posted:
    2567 messages
    Followed by:
    549 members
    Thanked:
    709 times
    GMAT Score:
    770
    Post Thu Sep 03, 2009 5:40 am
    If you have a square bracket, the interval also contains the "head" of the interval. If it's just a round bracket, then that head is not included.
    In your examples:

    [0,5] means 0 <= x <=5

    (0,5) means 0 < x < 5

    [0,5) means 0 <= x < 5

    Thanked by: winnerhere
    winnerhere Master | Next Rank: 500 Posts Default Avatar
    Joined
    12 Apr 2007
    Posted:
    231 messages
    Followed by:
    1 members
    Thanked:
    5 times
    Post Thu Sep 03, 2009 7:20 am
    Thanks danaj Smile

    what abt {}

    Post Thu Sep 03, 2009 2:21 pm
    Dana's explanation is perfect, but I've never seen a real GMAT question which uses that notation for an interval (ranges of values are always expressed using inequalities, a number line, or words), so you likely don't need to know it. In algebra, square brackets [] and parentheses () have the same meaning (in algebra texts, you'll sometimes see square brackets used as outer brackets when there are brackets within brackets), though I don't think I've ever seen that on the GMAT either - I'm pretty sure the GMAT uses standard parentheses exclusively in algebraic expressions. Set braces {} will only be used in a question about sets, so if you see something like {6}, that's the one element set containing the number 6.

    _________________
    If you are looking for online GMAT math tutoring, or if you are interested in buying my advanced Quant books and problem sets, please contact me at ianstewartgmat at gmail.com

    Thanked by: boxsope
    DanaJ Site Admin
    Joined
    01 Jan 2009
    Posted:
    2567 messages
    Followed by:
    549 members
    Thanked:
    709 times
    GMAT Score:
    770
    Post Thu Sep 03, 2009 10:11 pm
    On top of what Ian said, we also have this notation in Romania:

    {2.34} = 0.34
    {3} = 0

    We call this the "fractional part" of a number. However, seeing this on the GMAT is impossible, since I understand it is a pretty specific notation.

    Best Conversation Starters

    1 jjjinapinch 82 topics
    2 AbeNeedsAnswers 60 topics
    3 NandishSS 16 topics
    4 richachampion 12 topics
    5 Mayankaggarwal 10 topics
    See More Top Beat The GMAT Members...

    Most Active Experts

    1 image description Rich.C@EMPOWERgma...

    EMPOWERgmat

    114 posts
    2 image description Matt@VeritasPrep

    Veritas Prep

    80 posts
    3 image description Brent@GMATPrepNow

    GMAT Prep Now Teacher

    79 posts
    4 image description DavidG@VeritasPrep

    Veritas Prep

    75 posts
    5 image description Jay@ManhattanReview

    Manhattan Review

    73 posts
    See More Top Beat The GMAT Experts