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Re: Limit of Floor function

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  • Subject: [mg73938] Re: Limit of Floor function
  • From: dh <dh at>
  • Date: Sat, 3 Mar 2007 01:11:55 -0500 (EST)
  • References: <es6dgu$s4l$>

Hi Eric,

the answer depends on the direction from where you aproach the limit:

Limit[Floor[x],x->10,Direction->1] gives 9

Limit[Floor[x],x->10,Direction->-1] gives 10

The manual does not specify what the direction is in Limit[expr,x->x0], 

but obviously Direction->-1 is used by default.


Eric Smith wrote:

> Mathematica 5.2 evaluates one-sided limits of the Floor function

> correctly.  But if I just ask:


>    Limit[Floor[x],x->10]


> It replies "10".  Shouldn't it tell me the limit is undefined,

> since the Floor function has a step discontinuity at every integer

> value?


> Thanks,

> Eric


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