Number Line & Intervals (Part 1)

  • #1
mathdad
1,283
1
The set of real numbers satisfying the given inequality is one or more intervals on the number line. Show the intervals on a number line.

(A) |x| < 2

(B) |x| > 0

For (A), I must plot -2 < x < 2 on the number line. In interval notation it is written (-2, 2). Is this right?

For (B), we have the fact that x < 0 or x > 0. Does this mean there is an arrow to the left and right of zero on the number line? I do not understand why, in interval notation, we write (-infinity, 0) and (0, infinity).
 
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  • #2
This is how I would draw the intervals:

a)



b)

 
  • #3
MarkFL said:
This is how I would draw the intervals:

a)



b)


Cool. Is my math work correct, Mark? You must have a computer math software.
 
  • #4
RTCNTC said:
Cool. Is my math work correct, Mark? You must have a computer math software.

Yes, your math is all good. (Star)

For the diagrams, I used our TikZ feature. (Yes)

Click on the images to see the code I used to generate them. :D
 
  • #5
MarkFL said:
Yes, your math is all good. (Star)

For the diagrams, I used our TikZ feature. (Yes)

Click on the images to see the code I used to generate them. :D

I will check out Tikz feature. Does it also apply to cell phones?
 
  • #6
RTCNTC said:
I will check out Tikz feature. Does it also apply to cell phones?
As far as I know, but I don't use any mobile devices so I can't tell you for sure. :)
 
  • #7
MarkFL said:
As far as I know, but I don't use any mobile devices so I can't tell you for sure. :)
I want to thank you for being so attentive to my questions and for not passing judgement like a few others do. I joined this site to help me become a better math person. I enjoy math. I love precalculus.

Math helps me forget about the problems of life. I help elementary school students with math homework online and through in-person tutoring when time allows. I also help middle school students. It is because of websites like this one that I feel my math skills have greatly increased. I have more work to do in terms of word problems but one section at a time.
 

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