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Help with continous line graph (interval notation)

  1. Jan 27, 2013 #1
    1. The problem statement, all variables and given/known data
    See attachment: what is the interval notation of the continuous line


    2. Relevant equations
    no equation


    3. The attempt at a solution

    (-2,-1)U(-1,inf) ? not sure then it goes to 1 then to -inf? There are two continuous lines
    (-2,-1)U(-1,1)U(1,inf)? No....
    i feel like an idiot on this problem
     

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    Last edited: Jan 27, 2013
  2. jcsd
  3. Jan 27, 2013 #2

    SammyS

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    What is the function's value at x = 0 ?
     
  4. Jan 27, 2013 #3
    idk inf?
     
  5. Jan 27, 2013 #4

    SammyS

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    ∞ is not a permissible value for a function.

    Is the function even defined at x = 0 ?
     
  6. Jan 27, 2013 #5
    Sorry and no it's not I believe. Nothings there. From -1 there is discontinuity and a jump to 1
     
    Last edited: Jan 27, 2013
  7. Jan 27, 2013 #6
    I'm really having trouble with this problem
     
    Last edited: Jan 27, 2013
  8. Jan 27, 2013 #7

    SammyS

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    Read the Forum rules regarding bumping.
     
  9. Jan 27, 2013 #8

    SammyS

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    The function is not defined at x=0, so how can it be continuous there? (You said it was continuous on (-1,1) . )
     
  10. Jan 27, 2013 #9
    I'm stuck after (-2,-1) if that's even right for the first continuous line

    So there is a hole after -1. Then there is jump to 1 so that (-1,1) doesn't apply since at 0 it's undefined. So from 1 onto where? at 1 there are 2 holes, one going infinitely down and another that goes right

    Not continuous:
    1.) not defined
    2.) limit DNE
    3.) limit does not equal to evaluation --> is this the problem? this last one
     
  11. Jan 27, 2013 #10
    (-2,-1)U(-1,0)U(0,1)U(1,3)U(3,4) ? Nope.. How do I do this??????
     
    Last edited: Jan 27, 2013
  12. Jan 27, 2013 #11

    SammyS

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    What do you mean by "continuous line" ? You're looking for continuity over a set of intervals.


    Why do you say the graph is not continuous at x=3 ? (Which of the three above reasons?)
     
  13. Jan 28, 2013 #12
    I know the answer finally. The problem was that I had it all along, but everytime I typed it into the box online it would not recognize it due to simple [] in which that's why I was so confused...

    The answer is: [-2,-1)U(-1,0)U(0,1)U(1,4]

    -Thanks
     
  14. Jan 28, 2013 #13
    (1,4]

    The previous answers I was posting was simply out of confusion since I've typed in the right answer before and was marked as incorrect, hence my confusion.

    Thank you
     
  15. Jan 28, 2013 #14

    Mark44

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    I'm not sure that the people who replied in this thread even understood what the problem is. "Interval notation of the continuous line" makes no sense whatsoever.

    Were you supposed to write interval notation for the graph you attached?
     
  16. Jan 28, 2013 #15
    Yes, writing the continuous line in interval notation. Which if done right you can identify the jumps or moments of discontinuity.
     
  17. Jan 28, 2013 #16

    Mark44

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    That's not what I said. The goal of the exercise, I believe, was to write the domain of the function in interval notation.
     
  18. Jan 28, 2013 #17
    Yes, but it didn't state that specifically in the problem. It simply just said write in interval notation of the continuous line and if there is more then one interval use a union sign. It's fine now though, I figured out the answer and the main reason why I couldn't figure it out was because the site wanted a bracket at the beginning and end, simple mistake which confused me into thinking one of the right answers I plugged in didn't work. I believe the other users knew what my question was because they were guiding me in the right direction.
     
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