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Homework Help: Trying to understand an integration example

  1. Feb 11, 2012 #1

    I am having some trouble understanding an integration example we have. I have written it out in the attached pdf. I would be grateful if someone can help me undertand what is going on.

    I assume you let a = (x-RP)/(√2 ΔRP) da to make the process easier, but I am, not sure how that becomes

    1/(√2 ΔRP) dx

    I thought if we took the top line to be a constant, that should have come out as zero?


    Attached Files:

  2. jcsd
  3. Feb 11, 2012 #2


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    You make the substitution a = (x-RP)/(√2 ΔRP) , then take the derivative of this with respect to x. Everything but x is treated as a constant, so this gives
    da/dx = 1/(√2 ΔRP), or dx = (√2 ΔRP) da.
  4. Feb 11, 2012 #3

    Thanks for the reply. Right, yea, I think I understand that ...I will run through it a few times just to make sure.


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