1. ## Question about pre-calculus notation

I am working through a practice exam and I see what looks like a bracket (it has squared edges, not rounded) and there is an extra vertical line so instead of this: [ it is more like this: |[

It is basically a squared-off C with two lines at the back part. Can anyone tell me what this notation means for me to do? I would like to finish my exam review. Thank you

2. Hello,
I am working through a practice exam and I see what looks like a bracket (it has squared edges, not rounded) and there is an extra vertical line so instead of this: [ it is more like this: |[

It is basically a squared-off C with two lines at the back part. Can anyone tell me what this notation means for me to do? I would like to finish my exam review. Thank you
I think I can guess what you're talking about.
Code:
 ____
| |
| |
|_|__
And there's another one on the right, isn't it ?

You should have shown part of the exercise so that we have a support.

I've used a notation with my teachers : $\displaystyle x \in \bold{[}1,5\bold{]}$ means that x is an integer between 1 and 5.
Maybe there are other interpretations. So tell me if it makes a logical sense.