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Estimating uncertainty

  1. Apr 8, 2010 #1

    Say I have a function given by f(x)=a/x, where a is some real constant. I know that there is some uncertainty Δx on x, but I don't know what it is. I just know that it will fluctuate around some value.

    What is the proper way of determining how f(x) reacts to the uncertainty Δx? I mean, is there a way to find out if it is very sensitive to even small Δx or not?
  2. jcsd
  3. Apr 8, 2010 #2


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    f(x) is sensitive to small Δx in the order -a/x2 because Δf = f '(x)Δx = -(a/x2)Δx.
  4. Apr 9, 2010 #3
    Thanks. Is Δf = f '(x)Δx a definition regardless of how f(x) depends on x?
  5. Apr 9, 2010 #4
    Ok, I think I got it... Thanks!
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