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Homework Help: Please check my solution

  1. Apr 8, 2007 #1
    I have to differentiate (e^-x) ((1-x)^1/2) twice:

    The first time i differentiate i get

    (-e^-x) ((1-x)^1/2) + (e^-x) ((1-x)^-1/2) (-1/2)

    then differentiating this i get

    [(e^-x) ((1-x)^1/2)] - [(e^-x) ((1-x)^-1/2) (-1/2)] + [(-1/2e^-x) (1/2(1-x)^3/2) + ((1-x)^-1/2) (1/2e^-x)]

    are these correct?

    thankyou for checking
  2. jcsd
  3. Apr 8, 2007 #2


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    Homework Helper

    If you want someone to check something for details, you should make sure you've shown what you want checked clearly and unambiguously. What does this mean '(1/2(1-x)^3/2)'? Is it (1/2)*(1-x)^(3/2)), or ((1/(2(1-x))^3)/2) etc etc. That said there should be terms with (1-x) to the power of 1/2, -1/2 and -3/2 (not 3/2). Other than that ok, I think.
  4. Nov 23, 2008 #3
    First derivative is OK. Before differentiating for the second time please write the first derivative nicer by taking (1-x) out of the first term and do some adding. I am sure that simplification will result.
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