# What does [x] means in mathematics ?

by momentum
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 P: 32 what does [x] means in mathematics ? i have found [x]= "the greatest integer <=x " is this true ? then, what will be the answer of of ..... [3],[1.5],[-1.5],[3.5] i am trying to answer, please correct me [3]=3 [1.5]=1 [-1.5]=-1 [3.5]=3 are these correct ?
 Sci Advisor HW Helper P: 1,994 [] meaning greatest integer is a common use of the [], but it can vary.You should check whatever book your problems are from, they should define what they mean by the notation. If it is the greatest integer function, then "[-1.5]=-1" isn't correct. You want the greatest integer less than or equal to -1.5, so it can't be -1 as -1.5<-1.
 Sci Advisor PF Gold P: 1,384 So, in what way is the defintion for $$[ x ]$$ you've given different from $$\lfloor x \rfloor$$ ? - also given to be the symbol for the floor function, which matches the definition you gave. None, AFAIK, just a "who's the author" thing. IMO, it's just a bad nomen confusum problem. I've also seen it used in characteristic functions. Somebody ought to pick one use, and pitch the rest.... :) and penalize deviating authors 10 points for misuse. :)
 Sci Advisor HW Helper P: 9,396 What does [x] means in mathematics ? Rubbish, Jim: there are far too few symbols possible and far too meanings that need to be conveyed. Context makes it clear what is going on.
 Sci Advisor HW Helper PF Gold P: 12,016 Uniqe and fossilized use of symbols is counter-productive of developing flexibility of the mind. It is the definition AT HAND that matters, and if the chosen notation is convenient for its purpose.

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