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Homework Help: What is a Small Number?

  1. Oct 17, 2011 #1
    What is a "Small" Number?

    1. The problem statement, all variables and given/known data

    I am given the equation, and asked to find an approximation (using Taylor's Formula):
    [tex]E=\frac{q}{z^2(1-d/z)^2}-\frac{q}{z^2(1+d/z)^2}[/tex]
    I am also told that I can assume "z is much larger than d, so d/z is small."

    Does this mean that I can assume d/z = 0? This seems to be what that quote is suggesting.

    Is this what it's referring to?

    2. Relevant equations



    3. The attempt at a solution

    Nada.
     
    Last edited: Oct 17, 2011
  2. jcsd
  3. Oct 17, 2011 #2

    Dick

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    Science Advisor
    Homework Helper

    Re: What is a "Small" Number?

    No, you can't put d/z=0. Saying d/z is 'small' means |d/z|<<1. So small that you can put (d/z)^2 approximately equal to zero. I.e. ignore it compared with d/z.
     
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