# What do these wierd square brackets mean? [| |]

1. Jul 23, 2011

What do these wierd square brackets mean??? [| |]

1. The problem statement, all variables and given/known data
In my BC Calc summer homework (taking the course next school year), I came across these odd square brackets in a limit problem and have no clue what they mean. I've looked all over the internet and cannot find anything similar. They're like [] but have two vertical lines on each bracket instead of the just one.

this is the best representation I can give:
[| x - 1|]

The problem is this:
lim [| x - 1 |]
x -> 4

2. Relevant equations
N/A

3. The attempt at a solution
For now I just kind of ignored the brackets and just plugged in 4 for x and got 3.

Please help! I am thoroughly confused and extensively frustrated. >=(

2. Jul 23, 2011

Re: What do these wierd square brackets mean??? [| |]

the inside bars stand for the absolute value function. the outer brackets stand for the floor function I guess. I hope I understood your post correctly.

Last edited: Jul 23, 2011
3. Jul 23, 2011

### vkash

Re: What do these wierd square brackets mean??? [| |]

I think these brackets ( [ ] ) represent greatest integer function. [x] means greatest integer less than equal to x. In all the question that i have faced if it ( [ ] ) represent greatest integer function then it is mentioned in the question. Is it mentioned in your case ?

and | | modulas function. You need to learn this from book. And i am sure that it is modulas function
You need to learn about these two function before doing question.
I am not sure that [ ] represent greatest integer function if it is not mentioned.

what is answer it that limit does not exist.todays I am also learning limits.

Last edited: Jul 23, 2011
4. Jul 23, 2011

### SammyS

Staff Emeritus
Re: What do these wierd square brackets mean??? [| |]

Did they look more like ⟦ and ⟧ ? (I super-sized them for clarity.)