1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

What does this mean? modulus

  1. Oct 24, 2012 #1
    udhlG.png

    I thought |r| means the positive values of r? Why do they say it means -1<r<1? Also, if |r| means -1<r<1 then why do they say |r|<1 when |r| is already -1<r<1 ?
     
  2. jcsd
  3. Oct 24, 2012 #2

    Mark44

    Staff: Mentor

    No that's not what |r| means. It means all of the values of r that are within 1 unit of 0. That would include -.5, for example, not just positive values (and zero) of r.
    These two statements say exactly the same thing: |r| < 1 and -1 < r < 1. They are equivalent statements.
     
  4. Oct 24, 2012 #3
    |r| is it not the absolute value of r? if so then I don't understand how it can be negative.

    how can they also be equivalent when they said |r| is -1<r<1 then they are saying |r|<1, which is -1<r<1 < 1?
     
  5. Oct 24, 2012 #4

    Mark44

    Staff: Mentor

    Yes
    Who is "it"? There are two things we're talking about here - r and |r|. Which one do you mean?
    No. I didn't say "|r| is -1<r<1".

    I said that |r| < 1 (first statement) and -1 < r < 1 (second statement) were two statements that said exactly the same thing. They are equivalent statements.
    Now, who are "they"? I said that |r|<1 and -1<r<1 [STRIKE]< 1[/STRIKE] were equivalent statements
     
  6. Oct 24, 2012 #5

    Erland

    User Avatar
    Science Advisor

    There is a typo in the hint. It should be: |r|<1 means -1<r<1.
     
  7. Oct 24, 2012 #6

    Mark44

    Staff: Mentor

    To be honest, I didn't notice that. I have my browser open to less than full-screen width, and didn't notice that hint way off to the right.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: What does this mean? modulus
  1. What does this mean? (Replies: 2)

Loading...